Fungal Concentrations Research Articles

A pilot study of the in vitro efficacy of different concentrations of Duddingtonia flagrans for the control of gastrointestinal nematodes of sheep.

Duddingtonia flagrans is a nematode trapping fungus used for the control of gastrointestinal nematodes in livestock. The quantity of chlamydospores of D. flagrans required for the reduction of third-stage larvae (L3) of sheep gastrointestinal nematodes (GIN) is largely unknown, and a matter of discussion. The aim of this experiment was to determine in vitro the nematophagous activity of four different concentrations of D. flagrans (1000, 3000, 6250, or 11000 chlamydospores/ml) in the presence of varying numbers of GIN third-stage larvae (L3) (500, 1000, 1500). Additionally, the study sought to evaluate the efficacy of this fungus on Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus colubriformis and Chabertia ovina. The results showed that as fungal concentrations increased, so did the larval reduction of third-stage infective larvae in each test. L3s number was not a determining factor in the efficacy against GIN. The comparison between various concentrations of chlamydospores revealed significant differences, particularly between 1000 and 11000 chlamydospores (P≤0.05). Regarding the larval reduction of the GIN species considered, D. flagrans demonstrated the same effectiveness across all species tested. The results of the current study confirm the efficacy and underscore the importance of D. flagrans as an alternative for controlling of GIN.

The contribution and flow of microbial residual carbon in soil aggregates following forest restoration on the Loess Plateau, China

Understanding the dynamics of microbe-mediated soil organic carbon (SOC) is important for both soil carbon buildup and turnover. However, little is known about how forest restoration affects microbially-driven SOC dynamics, particularly at the aggregate level. This study assessed the distribution of bacterial and fungal residues among aggregate fractions (>0.25 mm, 0.25–0.053 mm, and < 0.053 mm), as well as how their contribution to SOC following forest restoration on the Loess Plateau, China. The results revealed that long-term forest restoration increased the SOC content, bacterial and fungal residual carbon contents in all aggregates size fractions. The highest contents of bacterial residues carbon (BRC) and fungal residue carbon (FRC) were found in the 0.25–0.053 mm aggregate fraction, followed by > 0.25 mm fraction. Forest restoration significantly enhanced the contribution of BRC and FRC to SOC in aggregates. Specifically, the contribution of BRC to SOC decreased with aggregate sizes, whereas the contribution of FRC to SOC increased with aggregate sizes. The fungal: bacterial ratio gradually decreased in aggregates along with forest restoration. The general direction of MRC flow was from silt and clay fractions, or micro-aggregates (MIA) to MIA or large macro-aggregates. These findings suggest that the increase in SOC after forest restoration was linked to changes in microbial communities, and the particle size of aggregates affect the contribution of MRC to SOC.

Efficacy of the entomopathogenic fungus, Metarhizium anisoplae, against Khapra beetle Trogoderma granarium (Coleoptera: Dermestidae) under laboratory conditions

The khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is an important pest of stored wheat worldwide. This study assessed the efficacy of two isolates of M. anisoplae (commercial and local isolates). Different conidial concentrations (1×108, 1×106, 1×104) conidia/ml-1 and fungal filtrate (100, 75, 50) % of M. anisoplae were evaluated. In both fungal isolates, corrected mortality of T. granarium after exposure varied according to fungal concentrations conidial concentration of conidia/ml-1, and the fungal filtrate at a concentration of 75% caused the highest mortality rates. In addition, mortality rates were significantly varied according to the beetle's developmental stage. Both isolates of M. anisoplae caused between 41 and 67.6 % reduction in total fecundity of the female adults. The results demonstrate no significant differences between the local isolate of M. anisoplae and commercial formulation (Met 52 EC). Further studies under commercial storage conditions are required. Keywords: Insects storage pests, biological control, Entomopathogenic fungi

Characteristics of bioaerosols under high-ozone periods, haze episodes, dust storms, and normal days in Xi’an, China

The characteristics of bioaerosols and their effects on human beings’ health have become a major public concern in the recent years. This study compared the characteristics of bioaerosols under different types of pollution (high-ozone [HO] episodes, haze episodes, and dust storms [DSs]), with those of bioaerosols on normal days (NDs) in Xi'an, China. The concentrations, diurnal variations, and size distribution of bacteria, fungi, and total airborne microbes (TAMs) were investigated. The results showed that the bacterial and fungal concentrations were the highest during DSs and on NDs, reaching 425.2 and 956.9 colony-forming units/m3, respectively. The concentration of TAMs was the highest during HO episodes, reaching 10.7 × 106 cells/m3, which was significantly higher than that during the other events. The maximum concentrations of bacteria and fungi during HO episodes were observed in the morning, while they appeared separately in the morning and evening during haze episodes. Bacteria and TAMs during DSs reached peak concentrations in the morning and evening, which is opposite to the particulate matter (PM) distribution pattern. On NDs, temperature and relative humidity had significant effects on bioaerosols. The size distributions of airborne bacteria exhibited bimodal patterns, whereas unimodal distributions were observed for fungi. Fungi mainly attached in fine particles (<2.1 μm) with proportions of 67.4% and 60.5% during haze episodes and DSs, respectively, which means that fungi were easily penetrated into the human respiratory system. The evaluation of influence factors revealed that PM2.5 and PM10 had negative effects on fungal concentration during DSs, and ozone concentration and temperature were inversely correlated with fungal concentration during HO episodes. These results provide valuable reference data for elucidating the formation and evolution of bioaerosols under different types of pollution.

Analisis Kualitas Udara (Parameter Jamur) pada Ruang Tunggu Puskesmas Perawatan Kassi-Kassi dan Non- Perawatan Tamangapa di Kota Makassar

Room air quality that does not meet the requirements is proportional to the number of germs in the room. Community Health Center are not only visited by sick people but also healthy people, so that puskesmas have the potential to become places for disease transmission. Mold is one of the microorganisms that can determine indoor air quality. The aim of this research is to determine air quality through the concentration of air mold, and the factors that influence the concentration of air mold in the waiting rooms of the Treatment and Non-Maintenance Health Centers. Waiting room air samples were taken at the Kassi-Kassi and Tamangapa non-care health centers using passive methods. Air samples were grown on SDA media. The results of this research were that there were 7 types of fungal isolates isolated from the Kassi-Kassi and Non-Care Health Centers in Tamangapa Makassar, namely: Aspergillus niger.,Aspergillus flavus.,Aspergillus nidulans.,Fusarium sp.,Rhizopus sp.,Saccharomyces sp.,and trichophyton rubrum. There was no significant difference in fungal concentrations in the waiting rooms of the Kassi-Kassi and Non-Care Tamangapa Makassar Health Centers. The average value of air mold concentration in the waiting room of the Kassi-Kassi Care Health Center has an average of 6.44 CFU/m3, while the Tamangapa Non-Care Health Center has an average of 6.44 CFU/m3, still below the maximum standard determined by WHO in 2009 regarding Mold and Dampness Indoor Air, namely less than 500 CFU/m3.

Characterization of fungal communities in aerosols: Coastal waters vs. open oceans

Bioaerosols have an important influence on both the environment and human health. Current research on bioaerosols more focuses on bacterial aerosols, while the research of fungal aerosols could not be neglected, especially in marine environments. We present a study on the spatial distribution of fungal communities in aerosols over the South Yellow Sea (SYS), the East China Sea (ECS) and the northwestern Pacific (NWP) in autumn, further taking into account the influences of particle size differences and environmental factors. We found that the fungal concentrations at the junction of the South Yellow Sea and the East China Sea (SYS-ECS) were significantly greater than those at the junction of the East China Sea and the NWP (ECS-NWP) and the NWP (NWP1, NWP2, NWP5, and NWP9) (p < 0.05). Spatial differences in the richness and diversity of fungal communities were observed across different sea areas. Additionally, both the concentration and richness of fungal aerosols gradually decreased with increasing off-coast distance, suggesting that the influence of terrestrial sources on fungal aerosols over coastal waters was higher than open oceans. According to CCA (canonical correspondence analysis), the fungal community structures in the northern China marginal seas (NCMS) were influenced by the water-soluble ions F−, NO3−, and Ca2+, which primarily originated from anthropogenic activities, whereas wind speed exerted a significant impact on fungal community structure in the NWP. These results illustrate that the community structures of fungal aerosols depend on sampling site locations, source areas, particle size, and transport mechanisms. This research contributes to the understanding of fungal aerosols over the marine environment and reveals the impacts of environmental factors on fungal aerosols.

Metatranscriptome of human lung microbial communities in a cohort of mechanically ventilated COVID-19 Omicron patients

The Omicron variant of the severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) infected a substantial proportion of Chinese population, and understanding the factors underlying the severity of the disease and fatality is valuable for future prevention and clinical treatment. We recruited 64 patients with invasive ventilation for COVID-19 and performed metatranscriptomic sequencing to profile host transcriptomic profiles, plus viral, bacterial, and fungal content, as well as virulence factors and examined their relationships to 28-day mortality were examined. In addition, the bronchoalveolar lavage fluid (BALF) samples from invasive ventilated hospital/community-acquired pneumonia patients (HAP/CAP) sampled in 2019 were included for comparison. Genomic analysis revealed that all Omicron strains belong to BA.5 and BF.7 sub-lineages, with no difference in 28-day mortality between them. Compared to HAP/CAP cohort, invasive ventilated COVID-19 patients have distinct host transcriptomic and microbial signatures in the lower respiratory tract; and in the COVID-19 non-survivors, we found significantly lower gene expressions in pathways related viral processes and positive regulation of protein localization to plasma membrane, higher abundance of opportunistic pathogens including bacterial Alloprevotella, Caulobacter, Escherichia-Shigella, Ralstonia and fungal Aspergillus sydowii and Penicillium rubens. Correlational analysis further revealed significant associations between host immune responses and microbial compositions, besides synergy within viral, bacterial, and fungal pathogens. Our study presents the relationships of lower respiratory tract microbiome and transcriptome in invasive ventilated COVID-19 patients, providing the basis for future clinical treatment and reduction of fatality.

Drought impacts African black beetle feeding on perennial ryegrass

interactions between plants, herbivorous insects and fungal Epichloë endophytes. However, water availability fluctuates, a phenomenon intensified by climate change, challenging the success of NewZealand’s pastoral industry. The impacts of climatic changes, such as intensifying drought, on pastoral insect pests have received little attention. In a no-choice bioassay, African black beetle (ABB) were fed semi-synthetic diets containing freeze-dried foliage material from drought-exposed and well-watered perennial ryegrass containing endophyte strains AR37 or NZCT, or with material free of endophyte (Nil). Diet consumption, beetle weight change, fungal alkaloid concentrations, phytohormones, and NRI (nitrogen reflectance index) concentrations were measured and compared. Except for AR37, ABB consumed more diets containing drought-exposed rather than well-watered material, with a 61% increase in Nil and a 50% increase in diets containing NZCT, though these effects were not accompanied by corresponding ABB weight changes. Here, we discuss the implications of these results on ABB damage in New Zealand pastures in the context of increasing drought and illustrate how spatial patterns of ABB damage could change over the next 75 years. Areas that do not currently have high populations of ABB such as Manawatū-Whanganui, Wairarapa and Marlborough will become increasingly vulnerable to damage.

Morphological and molecular identification of the local entomopathogenic fungus Purpureocillium lilacinum and its pathogenicity against the larvae of superworm Zophobas morio (Coleoptera: Tenebrionidae)

Entomopathogenic fungi (EPF) are used as a sustainable substitute for chemical insecticides and have been recognized as effective biocontrol agents for mitigating insect pest populations. In this study, a naturally-occurring beneficial EPF, Purpureocillium lilacinum CBBS3.12 (Hypocreales: Ophiocordycipitaceae) from a cabbage farm was isolated and identified by combining morphological and molecular (ITS rDNA region) diagnostic characters. Fungal morphological key characters were consistent with the established species description and were subsequently validated through their ITS rDNA sequences, showing high sequence similarities to P. lilacinum isolates from diverse geographical locations, such as Mexico, the USA, Austria, Israel, China, and India. Additionally, the pathogenicity of P. lilacinum CBBS3.12 against the last instar larvae of Zophobas morio (Coleoptera: Tenebrionidae) was investigated, revealing significant variations in insect mortality based on different fungal concentrations. The highest mortality was recorded at a concentration of 6.0 x 108 spores mL−1, 6 and 12 days post-inoculation. This investigation underscores the promising capabilities of P. lilacinum CBBS3.12 as a biocontrol organism targeting Z. morio. The present study warrants a more comprehensive evaluation of its virulence against diverse agricultural pests and the identification of its active metabolites and compounds to enhance our understanding of its potential application in pest management programs.

Soil-borne microbes, natural stimulants, and post-harvest treatments alter quality and phytochemicals of tomato fruit

ABSTRACT Various approaches have been used to improve the quality of tomato (Solanum lycopersicum. L.) fruit. Studies on the impact of soil-born microbe and natural stimulant inoculum on tomato fruit are limited. Concentrations of arbuscular mycorrhizal fungi (AMF) and licorice root extract (LRE) were applied to the soil under greenhouse conditions. How post-harvest period affected quality of tomato fruit was tested by storing fruit after harvest. All treatments reduced weight loss compared to the control. The LRE applications increased fruit hardness, cohesiveness, and total sugar. Integrated AMF with LRE treatments improved fruit hardness, springiness, and cohesiveness increased. Overall, pH, total soluble solids, total sugar, total phenol, and chlorophyll contents of the fruit were increased, however, total acidity and vitamin C decreased. The AMF and LRE applications can be used to improve tomato fruit quality and yield.

Airborne Culturable Fungi in Primary Schools

The aim of this current research was to investigate airborne fungi in indoor environments at primary schools. The study also examined the correlation between these fungi and building characteristics, as well as some geographical and meteorological parameters. To achieve this aim, a passive sampling method was used. In this study, 148 samples were collected from the indoor environments of 24 schools located in Qom, Iran. To collect the samples, passive sampling was performed using Petri plates containing Sabouraud dextrose agar (SDA). The characteristics of school buildings were evaluated by checklist. The mean ± SD fungal load of indoor air in selected schools was found to be 10.1 ± 14.0 colonies (CFU/dm2/ h). According to the IMA standard, the majority of the classes (71.7%) were in very good condition. The dominant species were as follows: Aspergillus niger, Aspergillus candidus, and Aspergillus flavus. Furthermore, the fungal load of girls’ schools was significantly higher than that of the boys' schools (p &lt; .05). The correlation analysis using the Pearson test showed that there was a direct correlation between the mean fungal load of classrooms and the number of students (p &lt; .01). The highest concentration of fungi was found on the ground floor and in poor ventilation conditions (p &lt; .05). During the study, it was found that schools located in the western part of Qom, Iran, had a higher concentration of fungi. This can be attributed to their exposure to the prevailing winds and the penetration of outdoor dusty air into indoor environments. The large number of students in each class and the inappropriate ventilation, which are the causes of airborne culturable fungi of these classes, call for the need for proper operation of school buildings.

Differences of airborne and mural microorganisms in a 1,500-year-old Xu Xianxiu's Tomb, Taiyuan, China.

Microbial colonization represents one of the main threats to the conservation of subterranean cultural heritage sites. Recently, the microbial colonization on murals in tombs has gradually attracted attention. In this study, a total of 33 samples, including 27 aerosol samples and 6 mural painting samples, were collected from different sites of Xu Xianxiu's Tomb and analyzed using culture-dependent methods. We compared the diversities of culturable bacteria and fungi isolated from the air and murals and explored the potential impacts of microorganisms on the biodeterioration of the murals. Phylogenetic analyses revealed that the culturable bacteria belonged to Bacillus, Microbacterium, Lysobacter and Arthrobacter. And the most of fungal belonged to the Penicillium, Cladosporium and Aspergillus genera. The composition and structure of airborne bacteria and fungi outside the tomb were both significantly different from that inside the tomb. The variation trends of airborne bacterial and fungal concentrations at different sampling sites were remarkably similar. Bacillus frigoritolerans, Bacillus halotolerans, Bacillus safensis, Exiguobacterium mexicanum, Microbacterium trichothecenolyticum, and Micrococcus yunnanensis were bacterial species commonly isolated from both the mural and air environments. Fungal species commonly isolated from aerosol samples and mural painting samples were Alternaria alternata, Cladosporium cladosporioides, Penicillium brevicompactum, and Peyronellaea glomerata. The prediction of the ecological functions of the bacteria revealed that chemoheterotrophy or aerobic_chemoheterotrophy accounted for substantial relative proportions in all sample types. These results suggest that the aerosol circulation between the inside and outside environments of the tomb was weak and that the outside environment had yet to have an impact on the air microbial community inside the tomb. Selective colonization of microorganisms, which is mediated by interaction between microorganisms and special microenvironmental factors, is an important reason for the biodeterioration of murals.

A robust hydroponic‐based system for screening red clover (Trifolium pratense) for Fusarium avenaceum

AbstractRed clover (Trifolium pratense) is an important forage legume crop that suffers like most perennial crops from attacks by soil‐borne pathogens. Fusarium root rot is one of the most serious diseases and at the same time problematic to identify resistance because of its hidden life in the soil. Current screening methods are laborious and hampered by limited reproducibility. To remedy this situation, we aimed to establish a simple and reliable hydroponics‐based screening system to facilitate studies of red clover–Fusarium avenaceum interactions. First, the fungal spore concentrations were balanced toward the development of red clover plants grown hydroponically. We found that the optimum concentration was 30,000 spores in 2 L of hydroponic medium to ensure infection during the plant growth period in this system. The procedure was scaled‐up to screen plants from 25 populations to identify red clover individuals with the improved resistance to F. avenaceum. Susceptible plants had approximately two‐fold higher amounts of fungal DNA than resistant plants, demonstrating a correlation between the disease readings of the plants and pathogen DNA. We foresee this screening procedure meeting the needs of both applied breeding work and in‐depth molecular studies of responses between this pathogen and its host plant. This method could be applied for the screening of other plant species for resistance to Fusarium spp. or to other root microbes.

Assessment of fungal contamination and biosecurity risk factors in duck-breeding farms in South Korea

Fungi are pathogens that infect all types of poultry and farmers, leading to economic losses in poultry production. Fungi can be isolated from environmental samples and are ubiquitous in the air. This study aimed to evaluate fungal contamination in domestic duck farm environments and analyze biosecurity risk factors associated with fungal infection incidence to assess the vulnerability of the farms to fungal infection. The average fungal concentration was 203 colony-forming units (CFU)/m3 in the air and 365×103 CFU/m2 in the wall surface samples. Sixteen fungal genera were recovered from air and wall surface samples from 19 duck-breeding farms, Aspergillus being the most frequently isolated (air: 43.2%; wall surface: 40%). Eleven additional fungal genera (Acrophialophora, Byssochlamys, Fusarium, Lichtheimia, Paecilomyces, Penicillium, Polycephalomyces, Rhizomucor, Scopulariopsis, Talaromyces, and Thermoascus) were isolated from air samples. Also, 8 additional fungal genera (Chaetomium, Lichtheimia, Penicillium, Petriella, Rhizomucor, Rhizopus, Talaromyces, and Trichosporon) were isolated from wall surface samples. The characteristics of the poultry farms (geographic region, stocking density, breeding house type, affiliate, duck age, and season) and fungal concentrations in the air and wall surface samples were analyzed to evaluate the biosecurity risk of the farms. Fungal infections were significantly affected by high stocking density (>2 ducks/m2), duck age (18-25 wk and >60 wk), and high fungal concentration in the wall surface samples (>300×103 CFU/m2).

Artificial intelligence unveils key interactions between soil properties and climate factors on Boletus edulis and B. reticulatus mycelium in chestnut orchards of different ages

The main objective of this study was to determine the possible interaction of two important abiotic factors (soil and climate) on the mycelial concentration and frequency of the ectomycorrhizal fungi Boletus edulis and B. reticulatus, using traditional statistics and artificial neural network tools. The frequency and concentration of Boletus mycelium were determined over three months (September, October, and November), and two years (2018 and 2020), in three hybrid chestnuts (Castanea × coudercii) orchards of 40-, 10-, and 3- years-old, using real-time qPCR. Statistical analysis revealed a significant effect of the year on B. edulis mycelium concentration and of the sampling plot (different tree ages) on B. reticulatus frequency. The combination of artificial intelligence networks (ANN) with fuzzy logic, named neurofuzzy logic (NF), allowed the construction of two robust models. In the first, using year, month, and sampling plot as inputs, NF identified hidden interactions between year and month on B. edulis mycelium concentration and between sampling plot and sampling month on B. reticulatus mycelium frequency, thus improving the information obtained from the statistical analysis. In the second model, those three factors were disaggregated into 44 inputs, including 20 soil properties and 24 climatic factors, being NF able to select only 8 as critical factors to explain the variability found in both ectomycorrhizal Boletus species regarding mycelial frequency and concentration. Specifically, NF selected two chemical soil properties (cation exchange capacity and total carbon) and three physical properties (macroaggregates, total porosity, and soil moisture at field capacity), as well as their interactions with three climatic elements (cumulative difference between precipitation and potential evapotranspiration (P-PET-1-2) and water deficit (WD-1-2) in the previous two months and excess water (WE-1) in the month prior to sampling. These results provide a much deeper understanding and new insights into the ecology and the role of abiotic factors which explain the different mycelial development patterns of ectomycorrhizal fungi such as B. edulis and B. reticulatus in chestnut agroecosystems.

Evaluation of fungal diversity and mycotoxin content in pig feed containing clusterbean (Cyamopsis tetragonoloba) meal

Evaluation of fungal diversity and mycotoxin content in pig feed containing clusterbean (Cyamopsis tetragonoloba) meal

Assessment of Fungal Aerosols Dispersion from Municipal Solid Waste Disposal Site: A Case Study of Karaj, Iran

Introduction: Fungal aerosols from landfill sites can play a fundamental role in environmental pollution and health. The present study aimed to assess the dispersion of fungal aerosols from municipal solid waste disposal site.&#x0D; Materials and Methods: In this cross-sectional study, the concentration of fungal aerosols was determined in four geographical directions at distances of 250, 500, 750, and 1000 m around landfill site. Relative humidity and temperature were also measured. Moreover the concentration and type of the fungal taxa isolated from landfill site under different environmental and metrological conditions were evaluated.&#x0D; Results: The results showed that the maximum and minimum concentrations of fungal aerosol in the landfill site were 256.18 ± 59.7 CFU/m3 and 76.56 ± 23.2 CFU/m3, respectively. The most frequent fungi detected from municipal landfill site included Penicillium (43.67%), Cladosporium (33.54%), Yeast (7.60%), Aspergillus (5.91%), Curvularia (3.62%), Chrysosporium (1.57%), Alternaria (1.54%), Scopulariopsis (0.84%), and Ulocladium (0.60%) taxa. The maximum identified fungal aerosol concentration in the area around the solid waste landfill was 350 CFU/m3. Furthermore, the concentration of fungal aerosols in the environment was significantly related to relative humidity, wind direction, and temperature in spring and winter (P &lt; 0.05).&#x0D; Conclusion: Municipal solid waste disposal site can be a potential source for fungal aerosol dispersion. Moreover, fungal aerosols concentration is correlated with wind direction and speed, relative humidity, and temperature

Poultry house as point source of intense bioaerosol emission.

Intensive poultry farming is usually associated with massive exposure to organic dust, which is largely composed of microbiological origin particulates. The aim of the study is to assess occupational and environmental exposures to airborne bacteria, fungi, and Marek's disease virus emitted by a poultry house. The concentrations of airborne microorganisms in a poultry house and its vicinity (250-500m) at 3 different stages of the production cycle (i.e. empty poultry house, with 7-day-old and 42-day-old chickens) were stationary measured using Andersen and MAS impactors, as well as Coriolis and BioSampler impingers. The collected microbiota was taxonomically identified using molecular and biochemical techniques to characterize occupational exposure and its spatial dissemination. Although Marek's disease virus was not present in the tested air samples, the appearance of reared chickens in the poultry house resulted in an increase in airborne bacterial and fungal concentrations up to levels of 1.26 × 108 CFU/m3 and 3.77 × 104 CFU/m3, respectively. These pollutants spread around through the ventilation system, but their concentrations significantly decreased at a distance of 500m from the chicken coop. A part of the identified microbiota was pathogens that were successfully isolated from the air by all 4 tested samplers. The poultry house employees were exposed to high concentrations of airborne microorganisms, including pathogens that may lead to adverse health outcomes. To protect them, highly efficient hygienic and technical measures regarding the poultry house interior and its ventilation, respectively, should be introduced to prevent both unwanted pollution and subsequent emission of microbial contaminants during intensive chicken breeding.

Culturable airborne fungi communities in naturally ventilated indoor spaces of old residential buildings in Poland

The fungal communities inhabiting apartments in multifamily buildings ( N = 33 apartments) with natural ventilation were determined during seasonal variation in the south part of Poland (Silesia region). It was found that the average level of CO2 concentration usually not exceeded 1000 ppm. The minimal value was noted in November – 402 ppm, however the maximal concentration was equal 6156 ppm and obtained in June. The average fungal colony forming units (CFU/m3) was calculated as follows: 1.06 × 102 (February), 1.17 × 102 (June) and 2.98 × 102 (November). The most frequently occurred species/genera: yeast and yeast-like fungi, Aspergillus niger, Penicillium spp., Cladosporium cladosporioides, Rhodotorula rubra; Culvaraia lunata, Dematiaceae family, Ulocladium consortiale, Verticillium spp.; Fusarium spp., Alternaria alternata; Oidiodendron griseum. The cluster analysis showed no mutual similarity between communities of air fungi isolated from bathrooms of all studied apartments as well as between communities isolated from other indoor spaces (rooms, kitchens, halls). This suggests that natural ventilation has no (or minimal effect) on the propagation of fungal spores between apartments. Statistically significant positive correlation between the concentration of fungi in the air and external humidity, carbon dioxide levels (February, November), and external temperature (November) were found. This study provides that natural ventilation has no effect on the spread of fungal spores inside the building and are not contributed to increase of fungal airborne health risk transmission. It also shows evidence of seasonal changes in carbon dioxide in multi-family homes with natural ventilation. This may give input to establish CO2 benchmark data in such type of buildings.

Endophytic colonization of sugar beet by Beauveria varroae and Beauveria bassiana reduces performance and host preference in army worm, Spodoptera littoralis

Spodoptera littoralis (Lepidoptera: Noctuidae) Boisduval 1833 is a voracious leaf feeder and major agricultural pest attacking numerous crops. Development of insecticide resistance hampers management efforts for S. littoralis and entomopathogenic fungi represent one possible alternative management tool. Here, we quantified colonization of sugar beet, Beta vulgaris L, with two fungal entomopathogens, Beauveria varroae Vuillemin 1912 and Beauveria bassiana (Balsamo) Vuillemin 1912 (Ascomycota: Hypocreales), and examined their endophytic effects on biological and reproductive parameters of S. littoralis. Two methods were used to inoculate sugar beet: soaking seeds in spore suspension and spray application of conidia onto leaves. For both methods, fungal suspensions with concentrations of 1 × 104 and 1 × 108 conidia/ml colonized roots, stems, and leaves of sugar beet. The colonization rate increased over time. Following inoculation of seeds, weight gain of S. littoralis larvae fed on leaves infected with endophytic fungi was reduced compared with controls. Furthermore, protease and lipase activities in the gut of S. littoralis decreased with increasing concentration of fungus applied to plants. An increase in phenol oxidase activity in the gut also indicated increased defense response of larvae feeding on Beauveria-infected leaves. Both B. bassiana and B. varroae decreased the duration of larval and pupal stages, adult emergence, and oviposition by females. Incubation of sugar beet seeds with B. varroae or B. bassiana decreased survival of pupae and egg laying by female moths on endophyte-infested treatments by 30 and 50%, respectively, compared with controls. Furthermore, an initially female biased sex ratio decreased toward 50:50 over time in populations of S. littoralis reared on sugar beet colonized by fungal endophytes as compared with controls, which remained female-biased. Endophyte inoculation increased growth of sugar beet compared with controls. Our results indicate that B. bassiana and B. varroae affect survival of S. littoralis and may be useful for management of this pest.