High Spore Concentrations Research Articles

Co-occurrence of airborne allergenic pollen grains and fungal spores in Rzeszów, Poland (2000-2002)

The co-occurrence of airborne allergenic pollen grains and fungal spores was estimated in Rzeszów in the years 2000-2002. The volumetric method was used in this aerobiological study. Six taxa of pollen grains and five types of fungal spores characterized by strong allergenicity and/or high concentrations in the air were analyzed. The time series of pollen grains and fungal spores were compared using PCA analysis. The periods of the greatest concentrations of tree pollen did not coincide with similar periods for herbaceous plants and fungal spores. From February to mid-March, <i>Alnus</i> pollen dominated in the air. The second period was characterized by <i>Betula</i> pollen. It occurred in April. Herbaceous pollen and fungal spores occurred in the air simultaneously (from mid May to the end of August), creating a risky situation for sensitized people. The periods of the highest concentrations of <i>Epicoccum</i> and <i>Ganoderma</i> fungal spores did not coincide with the same period for the examined plant taxa. In Rzeszów the probability of becoming exposed to very high concentrations of allergenic pollen and fungal spores at the same time was high, especially in July, when the highest concentrations of Poaceae, <i>Alternaria</i> and <i>Cladosporium</i> were noted. The hypersensitivity to only one plant or fungal allergen is rarely encountered. Under the present scenarios of global warming, pollen seasons of many taxa will be longer and sufferers will have year-long symptoms.

The estimation of fungal spore concentrations using two counting methods

The aim of the study was to estimate the spore counts of <i>Alternaria</i> and <i>Cladosporium</i> using the single longitudinal traverse and twelve transverse traverses methods. Both the single and twelve traverses methods generally showed similar average daily concentration fluctuations of the two studied spore types on the same days, although the single traverse method usually presented higher spore concentrations. However, analysing the distribution of concentrations obtained using both methods, there were days when the single or twelve traverses method showed a rise or fall in concentration which was not reflected by the other method. In case of <i>Cladosporium</i> higher daily concentrations obtained using the twelve traverses method occurred more frequently in the months of the highest spore concentrations. The higher concentrations of <i>Alternaria</i> spores obtained using this method occurred more frequently in the months of the lowest concentrations. Analysis of correlation (Pearson's correlation coefficient r) between those variables (number of days with higher concentration and monthly concentration) showed that the correlation was significant for <i>Cladosporium</i> and not significant for <i>Alternaria</i>, for both at the significance level α= 0.05. The results of the Wilcoxon's Paired Sample Test indicated that for both taxa the average daily concentrations obtained using the 1 traverse method were significantly higher than those obtained using the 12 traverses method.

Electrochemical inactivation of Bacillus spores in drinking water using a quaternary oxide electrode

Bacillus spores are resistant to disinfection methods and they represent a potential threat that requires improved methods to ensure water safety. Bacillus thuringiensis (BT) and B. anthracis Sterne (BA) spores were used to investigate the effectiveness of the electrochemical (EC) disinfection process. We tested the quaternary metal oxide (TiO2–Sb2O5–SnO2–RuO2) as the anode material in an EC cell for the inactivation of the spores. The presence of chloride ions at low concentrations was found to be critical for the effective inactivation of BT spores. Active chlorine was produced in-situ by anodic oxidation of chloride in the solutions. Local tap water used as a realistic test solution was found to contain average chloride concentrations of 1.2 mM. High concentrations of active chlorine were generated in the range of 0.35 to 0.5 mM (25 to 35 mg/L) to ensure that the high concentrations of spores were inactivated. We showed that the amount of active chlorine produced in the EC cell can be readily controlled by the operating conditions, including potential, flow rate and chloride content. Scanning electron images of the EC treated spores indicate damage to the outer membranes resulting in disruption and leakage of the spore contents. EC water disinfection processes using inexpensive electrode materials are a promising alternative as shown by inactivation of challenging biological threats such as Bacillus spores.

Purpureocillium, a new genus for the medically important Paecilomyces lilacinus

Paecilomyces lilacinus was described more than a century ago and is a commonly occurring fungus in soil. However, in the last decade this fungus has been increasingly found as the causal agent of infections in man and other vertebrates. Most cases of disease are described from patients with compromised immune systems or intraocular lens implants. In this study, we compared clinical isolates with strains isolated from soil, insects and nematodes using 18S rRNA gene, internal transcribed spacer (ITS) and partial translation elongation factor 1-α (TEF) sequences. Our data show that P. lilacinus is not related to Paecilomyces, represented by the well-known thermophilic and often pathogenic Paecilomyces variotii. The new genus name Purpureocillium is proposed for P. lilacinus and the new combination Purpureocillium lilacinum is made here. Furthermore, the examined Purpureocillium lilacinum isolated grouped in two clades based on ITS and partial TEF sequences. The ITS and TEF sequences of the Purpureocillium lilacinum isolates used for biocontrol of nematode pests are identical to those causing infections in (immunocompromised) humans. The use of high concentrations of Purpureocillium lilacinum spores for biocontrol poses a health risk in immunocompromised humans and more research is needed to determine the pathogenicity factors of Purpureocillium lilacinum.

HEAT RESISTANCE OF G. STEAROTHERMOPHILUS AND C. SPOROGENES IN CARROT AND MEAT ALGINATE PUREES

The main objective of this study was to investigate the heat resistance of nonpathogenic, heat-resistant Geobacillus stearothermophilus and Clostridium sporogenes spores in meat and carrot alginate purees. Alginate is used as a viscosity modifier in liquid foods and has been used to fabricate thermally stable and firm simulated particles for biological validation studies of thermal processing, when conventional temperature gathering is not possible. Pureed carrot and meat were mixed with sodium alginate and inoculated with high concentrations of spores of G. stearothermophilus or C. sporogenes and filled into capillary tubes, flame sealed and heat treated in an oil bath for different times at selected temperatures. D values were computed from the slopes of log(N/N0) versus time, and z values from log(D) versus temperature curves. For meat alginates, D values for G. stearothermophilus ranged between 1.9 min and 40.8 min with a z value of 11.7C and D values for C. sporogenes ranged between 0.9 min and 28.7 min with a z value of 10.1C. For carrot alginates, D values for G. stearothermophilus ranged between 1.9 min and 42.6 min with a z value of 11.5C and D values for C. sporogenes ranged from 1.1 min and 31.0 min with a z value of 10.2C. The results were also fitted to Weibull model, but the model did not result in any better fit than the conventional first-order model. PRACTICAL APPLICATIONS Thermal process establishment is generally based on gathered time temperature data from test cans under real processing conditions. There are many situation like aseptic processing, continuous flow biaxial rotary processing, etc. in which such temperature measurements are often difficult. Biological validation is generally considered useful in such processes to validate the processes as well as computer simulations. Such concepts have been tried to some limited extent in the past. With new thermal processing equipment and processes surfacing time and again, such concepts need to be redesigned. In order to successfully use such applications, thermal destruction kinetics data under controlled conditions are needed. This study provides thermal destruction kinetics baseline data for one such study making use of alginate-impregnated meat and carrot-simulated particles. Further, the study compare two modeling procedures: the conventional first-order log-linear model versus the log-nonlinear Weibull models.

Study of pollen and spores from the stomach of a fossil woolly rhinoceros found in the lower reaches of the Kolyma river

E). A study of the stomach contentsof the fossilized rhinoceros using palynological methods with the aim of establishing the particularities of itsdiet and recreating the paleofloristic conditions of theperiod of its existence was of great interest.A sample of the remnants of the stomach lump ofthe woolly rhinoceros was characterized by a high concentration of pollen and spores (more than1700 micrograins in one preparation). Most pollengrains were very well preserved.In the general spectrum, the pollen of grass plantspredominates (98.5%). Pollen from trees and bushesaccounts of 0.9%, and 0.6% are represented by spores(Table 1). The grass pollen composition is mainlyaccounted for by the pollen of Gramineae (45.9%)and Compositae (40.6%), in which wormwood pollendominates (40.1%). Up to 10 varieties of pollen can bedistinguished in the Gramineae pollen by morphological characteristics. They differ in size, grain shape,pore, and exine structure, etc. It is very difficult toclassify the Gramineae pollen down to the specieslevel, and this has not been done yet. Nonetheless,judging by the morphological particularities of thepollen, it can be assumed that it belongs to differentGramineae species. Wormwood pollen is also represented by various species; on the basis of its morphology, we assume that it is composed of

Deposition of Bacillus subtilis spores using an airbrush-spray or spots to study surface decontamination by pulsed light

Microbial contamination on surfaces of food processing equipment is a major concern in industries. A new method to inoculate a single-cell layer (monolayer) of microorganisms onto polystyrene was developed, using a deposition with an airbrush. A homogeneous dispersion of Bacillus subtilis DSM 402 spores sprayed on the surface was observed using both plate count and scanning electron microscopy. No clusters were found, even with high spore concentrations (10 7 spores/inoculated surface). A monolayer of microorganisms was also obtained after deposition of 10 μL droplets containing 3 × 10 4 spores/spot on polystyrene disks, but not with a higher spore concentration. Pulsed light (PL) applied to monolayers of B. subtilis spores allowed log reductions higher than 6. As a consequence of clusters formation in spots of 10 μL containing more than 3 × 10 5 spores, log reductions obtained by PL were significantly lower. The comparative advantages of spot and spray depositions were discussed.

Improved Production of Bacillus thuringiensis by Intermittent Fed-Batch Culture with Total Cell Retention

Intermittent fed-batch culture with total cell retention was evaluated during Bacillus thuringiensis serovar. kurstaki fermentations aiming to enhance biomass and spore concentration yields while maintaining toxicity. This method is derived from the already reported intermittent fed-batch culture and utilized a tangential flow filtration system for cell retention. After 4 pulses, we obtained a biomass of 74.36 g·L-1 and this biomass displayed a half lethal concentration towards neonate Spodoptera frugiperda larvae of 40.53 ng·cm-2, and spore concentration of 4.6 x 1014 CFU mL-1. On the other hand, volumetric productivity was increased seven-fold compared to batch fermentation. Interestingly, we are not aware of higher spore concentrations reported to date for B. thuringiensis cultures.

Effects of meteorological factors on the levels of Alternaria spores on a potato crop

Alternaria solani Soraeur produces early blight in Solanum tuberosum L., leading to significant agricultural losses. The current study was carried out on the extensive potato crop situated in north-western of Spain during 2007, 2008 and 2009. In this area potato crops are the most important source of income. In this work we used a Hirst-type volumetric spore-trap for the aerobiological monitoring of Alternaria spores. The highest spore concentrations were recorded during the 2009 cycle (10,555 spores), and the lowest concentrations were recorded during the 2008 cycle (5,471 spores). Over the 3years of study, the highest concentrations were registered during the last stage of the crop. The aim of the study was to observe the influence of meteorological factors on the concentration of Alternaria spores, which can lead to serious infection and early blight. Prediction of the stages during which a crop is particularly vulnerable to infection allows for adjustment of the application of fungicide and is of environmental and agricultural importance. For this reason, we tested three models (P-Days, DD and IWP) to predict the first treatment and decrease the negative effect that these spores have on potato crops. The parameter that showed the most significant correlation with spore concentrations was minimum temperature. We used ARIMA (autoregressive integrated model of running mean) time-series models to determine the forecast. We considered weather data as predictor variables and the concentration of spores on the previous day as the fixed variable.

Allergic Fungal Rhinitis and Rhinosinusitis

The intent of this article is to review the published literature addressing the role of fungi as causative agents in allergic rhinitis and rhinosinusitis. Ambient mold spores are widely distributed in nature, and an estimated 3 to 10% of the world's population is allergic to molds. There are compelling epidemiologic links between mold (fungal) allergy and illnesses such as asthma and "asthma with allergic rhinitis." Fungal allergy is more prevalent in areas of high ambient mold spore concentrations. However, epidemiologic studies have failed to demonstrate a direct relationship between fungal allergy and allergic rhinitis either via outdoor or indoor exposure. Fungal allergy is clearly linked to a subset of chronic rhinosinusitis (CRS) known as allergic fungal rhinosinusitis (AFRS). This condition represents an intense allergic response against colonizing fungi giving rise to formation of allergic (eosinophilic) mucin, mucostasis, and sinus opacification. A broader role for colonizing fungi has been postulated in CRS owing to the demonstration of fungi in mucus in the vast majority of cases of CRS, and in vitro studies demonstrating that certain fungi, particularly Alternaria, elicit a "modified" allergic response in patients with CRS that is independent of IgE.

The use of aerobiological methods for forecasting Botrytis spore concentrations in a vineyard

Grey mould, caused by Botrytis cinerea, is one of the most common diseases in Galician vineyards. Knowledge of local airborne spore concentrations is of great value for developing models to predict fungal propagule concentrations, thus enabling phytosanitary treatments to be applied when a real risk of infection is detected. In order to develop an accurate model for forecasting airborne B. cinerea spore concentrations, a phenological and aerobiological survey was carried out in a vineyard located in Galicia (north-west Spain), from 2004 to 2008. Phenological observations were made on 20 vines of each of three grape varieties (Treixadura, Godello and Loureira) using the BBCH standardised phenological scale. A Hirst-type volumetric spore-trap was used for the aerobiological monitoring. The study sought to chart Botrytis spore concentrations as function of grapevine phenological stage. The highest spore concentrations over the grapevine cycle as a whole were recorded in 2008 (37299 spores), and the lowest in 2005 (1700 spores). In the five study years, the highest concentrations were registered during stage 8 (berry ripening), stage 7 (fruit development) and stage 5 (inflorescence emergence). The weather-related parameters displaying the most significant correlation with spore concentrations were dew point and relative humidity. ARIMA (Autoregressive Integrated Model of Running Mean) time-series models was used to forecast daily spore concentrations, considering B. cinerea spore concentrations and weather data as predictor variables.

Evaluation of the biocontrol potential of various Metarhizium isolates against green peach aphid Myzus persicae (Homoptera: Aphididae)

Twenty-three isolates of Metarhizium anisopliae (Metschnikof) Sorokin and M. acridum (Driver & Milner) JF Bischoff, Rehner & Humber from non-aphid host insects around the globe were evaluated for their aphid biocontrol potential, which is not well known. The apterous adults of green peach aphid Myzus persicae (Sulzer) were exposed to the fungal sprays of 11.5, 99 and 1179 conidia mm(-2) and blank control in three leaf-dish bioassays. All the tested isolates except one were proven to be infective to the aphid species at 21 +/- 1 degrees C and 14:10 h light:dark photoperiod, causing corrected mortalities of 10.1-95.3% at the high spore concentration. The data from ten isolates causing > 50% mortality at the high concentration were found to fit a time-concentration-mortality model well, yielding parameters for the estimates of their LC(50) and LT(50) that vary with post-spray time and spore concentration respectively. Four isolates of M. anisopliae (ARSEF 759, 4132, 2080 and 576) had LC(50) values of 44-80 conidia mm(-2) on day 8 and LT(50) values of 4.9-6.8 days at 100 conidia mm(-2), with 91-98% of the killed aphids being well mycotised after death. The Metarhizium infectivity to M. persicae differs greatly among the tested isolates. The four mentioned isolates with desired virulence and sporulation potential are excellent candidates for microbial control of aphids.

A comparative study of <i>Colletotrichum</i> species causing anthracnose in <i>Hevea</i>

Colletotrichum acutatum and C. gloeosporioides are destructive fungi causing diseases in a wide range of plants. In many instances they are responsible for mixed infections. The present study revealed that the spore productivity is higher in slow growing species C. acutatum at all temperatures investigated. Spores of C. gloeosporioides germinated earlier but both reached a maximum after 7-8 hrs and in C. gloeosporioides the elongation of germ tubes was much faster. The temperature influenced greatly the germination of spores in the two species and self-inhibition of C. acutatum occurred at much higher spore concentrations than in C. gleosporioides. The germination response of dry smears to temperature change was poor in both the species and drying reduced germination. Free water was not essential but when present promoted germination in both the species. None of the spores germinated below 85% RH at RT. The slower growth rate of C. acutatum was also evident in the liquid medium. PG activity of C. acutatum was higher than that of C. gloeosporioides and molecular weights of the enzyme were significantly different in the two species. The activity of PL was more or less similar in the two species. In laboratory studies C. acutatum appeared to be less virulent than C. gloeosporioides.

Selective Adhesion of Bacillus cereus Spores on Heterogeneously Wetted Silicon Nanowires

The article reports on the selective adhesion of Bacillus cereus spores on patterned and heterogeneously wetted superhydrophobic silicon nanowires surfaces. Superhydrophilic patterns on superhydrophobic silicon nanowire (SiNW) surfaces were prepared by a standard optical lithography technique. Exposure of the patterned surface to a suspension of B. cereus spores in water led to their specific adsorption in superhydrophobic areas. Comparable results were obtained on a patterned hydrophobic/hydrophilic flat silicon (Si) surface even though a higher concentration of spores was observed on the hydrophobic areas, as compared to the superhydrophobic regions of the SiNW substrate. The surfaces were characterized using scanning electron microscopy (SEM), fluorescence spectroscopy, and contact angle measurements.

Effects of different growth forms of Mucor indicus on cultivation on dilute-acid lignocellulosic hydrolyzate, inhibitor tolerance, and cell wall composition

The dimorphic fungus Mucor indicus was grown in different forms classified as purely filamentous, mostly filamentous, mostly yeast-like and purely yeast-like, and the relationship between morphology and metabolite production, inhibitor tolerance and the cell wall composition was investigated. Low concentrations of spores in the inoculum with subsequent aeration promoted filamentous growth, whereas higher spore concentrations and anaerobic conditions promoted yeast-like growth. Ethanol was the main metabolite with glycerol next under all conditions tested. The yields of ethanol from glucose were between 0.39 and 0.42 g g −1 with productivities of 3.2–5.0 g l −1 h −1. The ethanol productivity of mostly filamentous cells was increased from 3.9 to 5.0 g l −1 h −1 by the presence of oxygen, whereas aeration of purely yeast-like cells showed no such effect. All growth forms were able to tolerate 4.6 g l −1 furfural and 10 g l −1 acetic acid and assimilate the sugars, although with different consumption rates. The cell wall content of the fungus measured as alkali insoluble materials (AIM) of the purely yeast-like cells was 26% of the biomass, compared to 8% of the pure filaments. However, the chitosan concentration of the filaments was 29% of the AIM, compared to 6% of the yeast-like cells.

Fungi and pollen exposure in the first months of life and risk of early childhood wheezing

Background:Many studies have found that the risk of childhood asthma varies by month of birth, but few have examined ambient aeroallergens as an explanatory factor. A study was undertaken to...

Airborne Spore Exposure in Typical School Buildings

RATIONALE: Air quality in public school buildings has been of increasing concern to parents of children with asthma and allergies. To examine the indoor airborne spore levels in typical school buildings, the following studies were conducted. METHODS: Six school buildings in 1 school district were evaluated for indoor spore levels. Airborne spores were collected using an Allergenco MK3 spore trap and evaluated microscopically for 25 fungal taxa. Collections were made during the school year between September and June. All school buildings were heated and air-conditioned and none had obvious HVAC problems. RESULTS: At the sites we made 260 indoor and 37 outdoor collections. Mean total spore counts were 467 per cubic meter indoors and 8470 outdoors. Mean indoor total spore count for individual schools varied from 105 to 625 and mean indoor Apergillus/Penicillium spore counts varied from 0 to 136. Cladosporium and Ascospores were the 2 taxa most frequently observed (97% and 94% respectively). Aspergillus/Penicillium spores were found in about 7% of collections and Stachybotrys spores were only seen in 2 of the indoor collections (< 1%). CONCLUSIONS: We conclude that spore levels in typical public school buildings are relatively low, often less than 10% of outdoor spore levels. Spores typically associated with damp indoor environments are likewise infrequently found. High concentrations of spores in school buildings (over 1000 per cubic meter) should therefore be considered unusual.

Susceptibility of immature stages of the locusts Schistocerca gregaria and Locusta migratoria migratorioides to the microsporidium Johenrea locustae and effects of infection on feeding and fertility in the laboratory

Second instar nymphs of African migratory locust, Locusta migratoria migratorioides, and desert locust, Schistocerca gregaria, were tested for their susceptibility to the microsporidium pathogen Johenrea locustae (Lange et al. 1996, Journal of Invertebrate Pathology, 68, 28) in the laboratory. Spores of J. locustae were produced from live L.m. migratorioides, a conspecific to L. migratoria capito. Locusta m. migratorioides and S. gregaria were exposed to wheat seedlings sprayed with 20 mL of three concentrations (106, 107 and 108 spores mL−1). Both second-instar nymphs of L.m. migratorioides and S. gregaria were susceptible to J. locustae infection at the three concentrations. There was no effect of concentration of the microsporidium on mortalities of S. gregaria (92–98%) 19 days postinfection. Adjusted mortality in L.m. migratorioides at 19 days post-exposure was 24, 43 and 80% at the corresponding treatment concentrations. The effect of infection on fecundity was tested on both L.m. migratorioides and S. gregaria. Spinach leaf discs were treated with different concentrations (0, 104, 105 and 106 spores mL−1) of J. locustae and presented to female insects for 24 h. Female L.m. migratorioides surviving infection as nymphs laid significantly fewer egg pods than untreated controls at all levels of exposure. The number of eggs per female was also significantly lower in treated lots than in the controls. Higher spore concentrations also adversely affected egg hatching rate. The effect of J. locustae infection on feeding was tested on S. gregaria. There was a significant decrease in food intake among S. gregaria nymphs treated only at the high concentration (106 spores mL−1).

Optimization of a fermentation process for bioinsecticide production by Bacillus thuringiensis

In an attempt to develop a cost-effective process for bioinsecticide production by B. thuringiensis, the feeding regime during aerobic cultivation of the bacterium was investigated and optimized. The process was designed as a two-stage process; a first stage of active growth, where glucose and other nutrients were adequately supplied to the growing cells over 12 h, followed by a second stage of 2 h for spore formation and toxin release. In order to maximize spore and toxin yield and productivity, different quantities of glucose and nutrients were fed separately to the growing cells in four different fermentation runs. In all runs, glucose was converted to bacterial biomass during the first stage and subsequently to spores and crystal protein during the second phase. The best results were obtained with a fermentation run supplied with 190 g glucose in 1500 ml. Up to 20.1 g of bacterial insecticides/l were recovered from fermentation broth with a glucose to toxin conversion yield of 0.159 g/g. Also, a markedly high spore concentration of 2.31 × 1012 c.f.u./ml was obtained. The spore–crystal protein mixture obtained was tested for its insecticidal activity against three of the most agronomically important pests. Among the bioinsecticide-treated insect pests, Egyptian cotton leafworm, Spodoptera littoralis was the most susceptible pest with the lowest LC50 of the bioinsecticides against its larval instar and the highest virulence against adults emerged later on from the surviving larvae.

Production ofBeauveria bassianaFungal Spores on Rice to Control the Coffee Berry Borer,Hypothenemus hampei, in Colombia

Two isolates of fungal entomopathogen Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) were grown on cooked rice using diphasic liquid-solid fermentation in plastic bags to produce and harvest spore powder. The cultures were dried and significant differences were found for isolates and time of harvest. The spores were harvested manually and mechanically and after the cultures were dried for nine days, when moisture content was near 10%. After harvesting, spores were submitted to quality control to assess concentration, germination, purity, moisture content, particle size and pathogenicity to the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae). Spore productivity on cooked rice was less than 1×1010 spores/g using both manually and mechanically harvesting methodologies. Germination at 24 hours was over 75% and pathogenicity against H. hampei was over 92.5%. This methodology is suitable for laboratory and field studies, but not for industrial production when a high concentration of spores are required for formulation and field applications.