Domestic exposure to fungi and total serum IgE levels in asthmatic children

We measured the number of airborne, viable fungi and house dust mite (HDM) allergen levels in the homes of a group of asthmatic children. Blood samples were drawn and the amounts of total and specific serum IgE were determined. The association between the number of fungal colonies, dust mite allergen exposure, and specific and total IgE was evaluated. The number of viable airborne fungi was high (20,543 CFU/m(3)) in those investigated houses. Der p1 concentrations on child's mattress exceeding 2 microg/g were found in 78.6% of the houses. A quantitative dose-response relationship was demonstrated between the exposure to viable, airborne molds and the amount of total IgE (r = 0.4399 and P = .0249) and the level was further increased in children with coexposure to viable fungi and HDM.     

The physiology and ecology of a novel, obligate mycophagous flagellate

Abstract To determine if conidia of the nematophagous fungus Drechmeria coniospora are subject to predation by soil protozoa, several sandy soils were enriched with 10⁹ conidia of this fungus per g dry soil. After incubation of the samples at 20°C for three weeks, a flagellate was detected as the most dominant mycophagous protozoan. Conidia of several fungi, with minimum diameters between 2 and 16 μm, supported growth of this flagellate, irrespective of pigmentation. Bacteria however could not be used for growth, although bacteria and also latex beads of the same size were ingested. This is, to our knowledge, the first report of an obligate mycophagous soil-borne flagellate. The flagellate was able to grow at the expense of the conidia of D. coniospora in liquid culture, with a specific growth rate of about 0.1 h⁻¹; the optimum temperature was 20–24°C. Approximately 10 D. coniospora conidia were required for one flagellate division. In sterilized soil, enriched with 10⁸ D. coniospora conidia per g dry soil, the specific growth rate was 0.014 h⁻¹, when the soil was at 50 or 65% of its water-holding capacity (WHC). In drier soil, i.e. 25% WHC, no growth took place. During growth of the flagellate in soil, the number of D. coniospora was reduced by about 20%, which was in the same order of magnitude as expected on the basis of the requirement of 10 D. coniospora conidia for one flagellate division. Since many conidia remained in the soil after growth of the flagellate, we concluded that although the flagellate is an interesting organism, it does not play a very important role in the survival of D. coniospora conidia in the soil.     

The effect of house design and environment on fungal movement in homes of bronchial asthma patients

The effect of house building design and environment on the fungal movement in the houses of 41 bronchial asthma (BA) patients has been investigated by examining house dust. The presence and composition of fungi were determined and compared in relation to building structure, house age, size of living room, main flooring material, presence of a living-room rug or air purifier, and frequency of vacuum cleaning. Among these elements, fungal CFU apparently varied only between building structure: wooden-board houses had significantly higher numbers of fungi than reinforced concrete houses (p < 0.01), and wooden mortar or iron-framed prefabricated houses had significantly higher numbers of fungi than reinforced concrete houses (p < 0.05). Classification of the types of fungi present in the house dust of BA patients showed that, regardless of the building designs, there were high levels of osmophilic fungi (group A) and fungi that survive at relatively dry conditions (group B), whereas fungi that survive in very wet conditions (group D) were present at low frequency. This revised version was published online in August 2006 with corrections to the Cover Date.     

The effects of temperature and pH on the ethanol tolerance of the wine yeasts, Saccharomyces cerevisiae, Candida stellata and Kloeckera apiculata

The influences of temperature and pH on the survival and growth of Saccharomyces cerevisiae, Candida stellata and Kloeckera apiculata were examined in the presence of ethanol concentrations between 2.5 and 15% v/v. At 15°C, the maximum concentrations of ethanol permitting the growth of S. cerevisiae, C. stellata and K. apiculata were 15%, 11% and 9%, respectively. These maximum concentrations were decreased at 10°C and 30°C. Cells of S. cerevisiae showed no loss in viability when incubated for 12 d at 10°C or 15°C in the presence of 15% ethanol but showed some loss at 30°C. Cells of C. stellata were tolerant of 12.5% ethanol at 10°C and 15°C but not at 30°C. Cells of K. apiculata were tolerant of 10–12.5% ethanol at 15°C but not at 10°C or 30°C. Sensitivity of the yeast cells to ethanol was marginally increased on decreasing the pH from 6-0 to 3–0.     

The ability of Tilapia mossambica (Peters) to enter deep water

Juvenile Tilapia mossambica (Peters) are extremely tolerant of depth and can compensate to a depth increase of 0 to 33 m in a few minutes. As the fish grow they become less able to compensate to deep water. At a total length of 15–18.5 cm small adult male T. mossambica can compensate to 20 m whereas females can only compensate to 13 m. Large adults (20–25 cm) of both sexes compensated to 11.5 m (range 9.5–13 m). Adult fish require 4 to 7 days for maximum depth compensation at 22°C. Analysis of the oxygen content of the swimbladder indicated that this gas accounts for over half the gas in surface equilibrated fish. Oxygen secretion into the swimbladder appears to be the mechanism of equilibration at depth.     

House-dust community (Fungi,mites) in different climatic regions

Summary House-dust flora and fauna were compared in the maritime cool temperate climate (in three degrees of continentality), the mediterranean warm temperate climate, the arctic climate and the tropical climate.An inverse relationship exists between continentality of the temperate climate and the numbers of arthropods and fungi (mesophilic as well as xerophilic) in the dust of the houses.The numbers of arthropods and fungi were lowest in mediterranean and arctic climates, most likely because of the limiting effect of the drier indoor climate. Fungi are more tolerant of dry conditions than house-dust inhabiting mites. Generally the highest numbers of fungal diaspores and arthropods were found in the tropics, where, however, the lowest number of positive samples was also found, especially for the species of the Aspergillus glaucus group and for Wallemia sebi. Maritime cool temperate climate showed the highest numbers of positive samples for fungi and mites.In general, a relationship exists between relative humidity and the density of fungal diaspores and arthropods.Supported by grants no. 294 and 78.30 of the Dutch Asthma Foundation     

Ochratoxin A in airborne dust and fungal conidia

Farm workers are often exposed to high concentrations of airborne organic dust and fungal conidia, especially when working with plant materials. The purpose of this investigation was to study the possibility of exposure to the mycotoxin ochratoxin A (OTA) through inhalation of organic dust and conidia. Dust and aerosol samples were collected from three local cowsheds. Aerosol samples for determination of total conidia and dust concentrations were collected by stationary sampling on polycarbonate filters. Total dust was analysed by gravimetry, and conidia were counted using scanning electron microscopy. A method was developed for extraction and determination of OTA in small samples of settled dust. OTA was extracted with a mixture of methanol, chloroform, HCI, and water, purified on immunoaffinity column, and analysed by ion-pair HPLC with fluorescence detection. Recovery of OTA from spiked dust samples (0.9–1.0 μg/kg) was 74% (quantitation limit 0.150 μg/kg). OTA was found in 6 out of 14 settled dust samples (0.2–70 μg/kg). The total concentration of airborne conidia ranged from < 1.1 × 10⁴ to 3.9 × 15⁵ per m³, and the airborne dust concentration ranged from 0.08 to 0.21 mg/m³. Conidia collected from cultures of Penicillium verrucosum and Aspergillus ochraceus contained 0.4–0.7 and 0.02–0.06 pg OTA per conidium, respectively. Testing of conidial extracts from these fungi in a Bacillus subtilis bioassay indicated the presence of toxic compounds in addition to OTA. The results show that airborne dust and fungal conidia can be sources of OTA. Peak exposures to airborne OTA may be significant, e.g., in agricultural environments. This revised version was published online in August 2006 with corrections to the Cover Date.     

Storage of pathogenic leptospires in liquid nitrogen

The virulence and viability of various serovars of Leptospira interrogans were successfully preserved by storage in liquid nitrogen. Dimethyl sulphoxide at a final concentration of 2.5% (v/v) was added as cryoprotectant to a culture of leptospires grown in Ellinghausen-McCullough-Johnson-Harris medium. Ampoules were cooled at a controlled rate of 1°–3°C/min to −70°C, then transferred to the liquid phase of a liquid nitrogen storage unit. Glycerol was discounted as a cryoprotectant as it was found to be approximately 10 times more toxic than dimethyl sulphoxide to four of five serovars used in this study. The viability of nine strains has so far been observed over a period of 8–22 months storage in liquid nitrogen and full viability of all strains has been preserved over this period. Virulence of strains of serovars pomona and hardjo was well preserved, as demonstrated by challenge tests in guinea pigs and domestic pigs.     

The Disinfecting Activity of Methyl Bromide on Various Microbes and Infected Materials under Controlled Conditions

S ummary : Various micro-organisms were exposed to methyl bromide (MeBr) gas at concentrations of 20–40 mg/l for 20 h at 25°. A significant reduction was obtained in the number of viable bacteria and Aspergillus fumigatus spores, both in the dry form and in semifluid faeces, but no reduction was detected either in dried Bacillus subtilis spores or in one of the bacteriophages tested. The investigation indicates that MeBr is less effective against certain viruses, bacteria and fungi than against coccidial oocysts. The results suggest that fumigation of commercial poultry houses with these concentrations of MeBr may not, in all circumstances, provide the overall reduction of poultry pathogens desired.     

Seasonal variation in freezing tolerance of the New Zealand alpine cockroach Celatoblatta quinquemaculata

1. The cold hardiness of the alpine cockroach Celatoblatta quinquemaculata was investigated. This species is found at 1360 m a.s.l. beneath schist slabs on the Rock and Pillar Range (Central Otago, New Zealand). Cockroaches were collected monthly from January to December 1996, and their LT₅₀ and supercooling points determined.
2. Celatoblatta quinquemaculata was freezing tolerant throughout the year, with a lower lethal temperature in winter of – 8.9 °C. Celatoblatta quinquemaculata was also found frozen under rocks in the field when the under-rock temperature was below – 3 °C, and could survive being frozen at – 5 °C for 4 days in the laboratory.
3. There was a marked decrease in LT₅₀ temperature from – 5.5 °C in April to – 7.5 °C in May. This coincides with decreasing temperatures from summer through autumn to winter, during which temperatures beneath snow-covered rocks may reach – 7.3 °C.
4. Supercooling points fluctuated during the year, with an increase from – 4.2 °C in autumn to – 3.4 °C in winter. Supercooling point was highest in spring, and changes in supercooling point do not appear to be related to changes in LT₅₀.
5. Recordings of environmental temperatures from the Rock and Pillar Range suggest that cockroaches may undergo up to twenty-three freeze–thaw cycles in the coldest month of the year, and that they may remain frozen for periods of up to 21 h. Maximum cooling rates recorded in the field (0.01 °C min^–1) were 100-fold slower than laboratory cooling rates, so survival estimates from laboratory experiments may be underestimates.     

Temperature- and salinity-dependent development of a Nordic strain of Ichthyophthirius multifiliis from rainbow trout

During the twentieth century evidence was presented which suggested the presence of various strains and races of the parasite Ichthyophthirius multifiliis Fouquet. However, ecological profiles of various parasite isolates from different climatic zones are sparse. Such stringent characterizations of parasite development at defined abiotic conditions could provide valuable criteria for the different races; profile comparison from various localities is one way to differentiate these strains. Baseline investigations were therefore performed on the associations between abiotic factors (temperature/salinity) and the development of theronts in tomocysts of I. multifiliis isolated from rainbow trout in a Danish trout farm. It was shown that tomocyst formation and theront development took place between 5 and 30°C. Development rates and sizes of theronts were clearly affected by temperature: theronts escaped tomocysts already after 16–27 h at 25°C and 30°C, whereas this process took 8–9 days at 5°C. Likewise, theront size decreased steadily from a maximum of 57.4 × 28.6 μm at 5°C to 28.6 × 20.0 μm at 30°C. This size variation was only partly associated with the number of theronts that appeared at different temperatures. The lowest number of theronts escaping from one tomocyst was indeed found at 5–7°C (mean 329–413). At 11.6, 17.0 and 21°C, the highest number of theronts appeared (mean 546–642). However, at 25 and 30°C, the number decreased (458 and 424, respectively). Additional studies on the salinity dependent development of the parasite (at 11.6°C) showed that salinities above 5 p.p.t. totally inhibited development. Even at 5 p.p.t. the developmental time significantly increased and the number of theronts produced from one tomocyst decreased.     

Long-term cryogenic storage of Neurospora crassa spores

Neurospora crassa on agar slants in ampules were frozen by direct immersion into liquid nitrogen and stored at −196 °C for 0–5.5 years. The survival, estimated as percentage germination of conidia, after warming, varied between 81.1 and 97.6%. Although there was a slight decline in survival immediately after the freezing treatment, no further significant decline has been detected during 5.5 years storage. The regression coefficients, (0.43, control, and 0.97, liquid nitrogen storage for 5.5 years), do not predict extinction of viability.     

Effect of temperature and water activity on in vitro germination of Monilinia spp.

Aims:  This study evaluated the effect of temperature (0–38°C) and water activity ( a _w: 0·87–0·99) on the lag phase prior to germination and the percentage of germination over time for Monilinia laxa , Monilinia fructicola and Monilinia fructigena .
Methods and Results:  More than 80% of viable conidia germinated at 25°C and 0·99 a _w within 2 h for M. fructicola and M. fructigena and 4 h for M. laxa . There was no germination at 38°C, and all three Monilinia spp. germinated at 0°C. At the lowest a _w (0·87), none of the Monilinia spp. was able to germinate at any of the incubation temperatures studied. Whereas at 0·90 a _w, conidia were only able to germinate at 15, 25 and 30°C for the three species studied, except for M. fructicola at 15°C. In contrast, at 0·95, 0·97 and 0·99 a _w, germination occurred at all studied temperatures less 38°C. Generally, the lag phase was longer at low levels of a _w (0·90–095), and differences were more evident as temperatures were far from the optimum (0–5°C).
Conclusions:  Germination and lag phase period were markedly influenced by temperature and a _w, and in general when conditions of temperature and a _w were suboptimal, the lag phase was longer and the percentage of germination was lower.
Significance and Impact of the Study:  Knowledge of the germination requirements of this fungus is important in order to understand their behaviour in natural situations and to provide baseline data required for the construction of new prediction models. Our study might be used to develop a predictive model to understand and control the disease caused by Monilinia spp.     

Alteration of protein patterns in black rock inhabiting fungi as a response to different temperatures

Rock inhabiting fungi are among the most stress tolerant organisms on Earth. They are able to cope with different stressors determined by the typical conditions of bare rocks in hot and cold extreme environments. In this study first results of a system biological approach based on two-dimensional protein profiles are presented. Protein patterns of extremotolerant black fungi – Coniosporium perforans, Exophiala jeanselmei – and of the extremophilic fungus – Friedmanniomyces endolithicus – were compared with the cosmopolitan and mesophilic hyphomycete Penicillium chrysogenum in order to follow and determine changes in the expression pattern under different temperatures. The 2D protein gels indicated a temperature dependent qualitative change in all the tested strains. Whereas the reference strain P. chrysogenum expressed the highest number of proteins at 40 °C, thus exhibiting real signs of temperature induced reaction, black fungi, when exposed to temperatures far above their growth optimum, decreased the number of proteins indicating a down-regulation of their metabolism. Temperature of 1 °C led to an increased number of proteins in all of the analysed strains, with the exception of P. chrysogenum. These first results on temperature dependent reactions in rock inhabiting black fungi indicate a rather different strategy to cope with non-optimal temperature than in the mesophilic hyphomycete P. chrysogenum.     

Efficacy of Beauveria bassiana (Bals.) Vuill. against the spruce bark beetle, Ips typographus L., in the laboratory under various conditions

Abstract:  In laboratory bioassays, the efficacy of the entomopathogenic fungus Beauveria bassiana against the spruce bark beetle, Ips typographus , was tested under various conditions. Four of the tested isolates and the commercial product Boverol^® caused 99–100% mortality when tested at a concentration of 1.0 × 10⁷ conidia/ml at 25°C. Using B. bassiana isolate 138 at a concentration of 1.0 × 10⁶, the median survival time (MST) was 6.1 d and significantly longer compared with the MST of 4.2 and 4.0 d at 1.0 × 10⁷ and 1.0 × 10⁸ conidia/ml, respectively. In the next experiment, the beetles were maintained on spruce bark, filter paper or artificial diet during the bioassay with Boverol^®, and significant differences in the MST of 3.6, 2.5 and 5.3 d, respectively, were noticed. The experiment with Boverol^® at different temperatures showed that the beetles lived significantly longer at 15°C (MST 8.7 d) than at 20, 25, 30 and 35°C. At 25°C, the beetles died most rapidly (MST 3.5 d). At different relative humidities (RH) of 40, 70 and 100%, nearly all beetles were dead after treatment with a suspension of Boverol^® at 1.0 × 10⁷ conidia/ml. At 40% RH, 49% of the untreated beetles died after 7 d. The best effects were achieved with the following bioassay: beetles were fed for three days on artificial diet, then dipped into a solution of 1.0 × 10⁷ conidia/ml and transferred on a piece of spruce bark in Petri dishes at 25°C and 70% RH.     

Investigation of a series of samples of house dust for the presence of fungi: Correlation with previous investigations of air-borne fungi and sensitivity tests on patients

Summary A series of 198 samples of house dust were collected by vacuum cleaners from the homes of patients with allergic disorders. Suspensions in various dilutions were inoculated on to Sabouraud's agar. Twelve common genera accounted for 89.5% of the fungi identified. The results are compared with previous surveys of outdoor air and with the results of scratch tests performed on 119 of the patients from whose houses the dust had been collected, using commercial extracts of 14 common genera of fungi. Of the genera to which patients reacted most commonly, six were extremely prevalent in house dust, and/or in outdoor air.Working with the help of a full-time grant from the National Health and Medical Research Council of Australia.     

Abundance of house dust mites in relation to climate in contrasting agricultural settlements in Israel

The correlation between climatic conditions and mite numbers in houses from rural areas was studied in 13 agricultural communities (kibbutzim and moshavim) in nine geo-climatic subregions of Israel. Mites were present in 97% of the dust samples. The average number of mites per gram of dust in the different localities ranged between 84 and 2053. The maximum number of mites (7440/g dust) was found in a carpet from a house in Geva Carmel in the northern coastal region. The most prevalent species of mites were Dermatophagoides pteronyssinus and Dermatophagoides farinae, which were found in 85.6% and 71.3% of the samples, respectively. The house dust mites D. pteronyssinus, D. farinae and Euroglyphus maynei constituted 94.8% of the mites. Most of the mites were isolated from the carpets and sofas (37.0% and 33.7%, respectively), and a smaller number from beds (29.3%). The smallest number of mites (< or = 250/g dust) were found at a minimum relative humidity (RH) of 30% and lower, with a maximum temperature of 32 degrees C and higher, i.e. in the Jordan valley and Negev mountains. A greater number of mites (250-500/g dust) were found at a minimum ambient RH of 35-40% and a maximum temperature of 32 degrees C and higher, i.e. the Hula valley. A large number of mites (500-1000/g dust) were found at a minimum RH of 35-40% with a maximum temperature of 30 degrees C and lower, i.e. in the Judean and Samarian range, as well as in upper Galilee. The largest number of mites (1000-2000/g dust) was found at a minimum RH of 45% and higher, with a maximum temperature ranging between 30 and 32 degrees C. These conditions occur in the coastal strip, the coastal plain and in the Judean and Samarian foothills. A monthly examination of two houses in Zova, a kibbutz in the Judean hills next to Jerusalem, and two houses from Palmachim, a kibbutz in the coastal region, revealed that the highest prevalence of mites was found in the months April-November and May-November, respectively. In Zova, the highest number of mites were found during the months of June and July while the highest concentrations of D. pteronyssinus-antigen (Der p I) were measured during the month of September. A positive correlation between mite numbers and the quantity of Der p I in house dust was found.     

Non-intrusive tracking of commercial broiler chickens in situ at different stocking densities

Unlike several other farm animal species, the broiler chicken remains unprotected by species-specific legislation. The densities at which broilers should be kept is a highly contentious issue—some studies have demonstrated increased welfare problems at higher densities, whilst a few others have, contrary to expectations, suggested that broilers may actually find crowds of other birds attractive. A tracking method was developed and used to provide an insight into the social preferences of commercial broiler chickens in situ—inside commercial, closed-system broiler houses. The aim was to simultaneously assess the relative impact of global measures of density, such as target and actual stocking densities and local measures of the social environment on the behaviour and route taken to feed by focal birds. Birds were tracked inside 20 commercial broiler houses across the UK. Results from this study show that stocking density per se seems to have little direct effect on the individual behaviours of focal broiler chickens. However, there may still be an indirect effect of stocking density on broiler behaviour, mediated through the local social environment.     

Combined Effects of Water Activity, pH and Temperature on the Growth and Spoilage Potential of Fungi

S ummary . An arbitrary parameter 'rejection time', i.e. the time required for a fungal inoculum to form a 2 mm diam. colony, was used to express the shelf life of jam after unsealing and exposure of the contents to airborne contamination. Individual and combined effects of water activity ( a_w ), pH value and temperature on rejection time of low sugar jam were estimated from the radial growth on agar of colonies of 9 fungi. The decreases in a_w (0·94–0·90) and temperature (25–15°) practicable for low sugar jam were more effective in increasing rejection time than the feasible decrease in pH value (3·7–2·9). The interaction between a_w and temperature was significant. The effect of the changes in a_w , temperature and pH on rejection time was broadly similar for media adjusted by either sucrose or glycerol. At a given a_w , moulds were slightly more tolerant of glycerol than sucrose but yeasts, except for the osmophile Saccharomyces rouxii , were markedly more tolerant of glycerol than sucrose.     

The effect of temperature on the ability of Tilapia mossambica Peters to enter deep water

The ability of adult Tilapia mossambica Peters to enter deep water was determined at 15, 22 and 30°C. At 30°C adults compensate to about 20m depth but at 15°C to only 7 m. Compensation is more rapid at high than at low temperatures. T. mossambica haemoglobin has a marked Root effect which is the same at 22 and 30°C. The oxygen affinity of the haemoglobin is higher at 15°C than at 30°C. There was no measurable difference in the rate of passive oxygen diffusion across the swimbladder wall in the temperature range 15–30°C. It is concluded that the ability to enter deeper water at higher temperatures is related to decreased oxygen affinity of the haemoglobin and higher rates of oxygen secretion and blood circulation.