Assessment of microbial aerosol emissions in an urban wastewater treatment plant operated with activated sludge process

Wastewater that enters wastewater treatment plants contains lots of pathogenic and nonpathogenic microorganisms which can become bioaerosols during treatment processes and pose health hazard to workers and nearby residents. The emission of the bioaerosols from an urban wastewater treatment plant in spring and summer in different locations and downwind of the plant adopting an extended mechanical aeration system was investigated. Samples of bacteria and fungi were collected within 6 months at 10 selected points by an Anderson one-stage impactor. The highest concentration of bacteria (mean 1373 CFU/m³, 741–2817 CFU/m³) and fungi (mean 1384 CFU/m³, 212–1610 CFU/m³) was found in downwind of the aeration basins. Statistical analysis showed a significant relationship between concentration of bacterial bioaerosols at downwind side of the aeration basins and wind speed (p value <0.05) and temperature (p value <0.05). Also, in the spring and summer, between the number of bacteria and fungi inside the plant and outside the plant (downwind) a significant correlation was observed (p value ≤0.05). The concentrations of bacteria at a distance of 500 m downwind were much higher than those at the background (upwind) point in spring and summer. The processes of wastewater treatment especially using mechanical equipment to create turbulence can be considered as a major source of spreading airborne microorganisms to ambient air of wastewater treatment plants, and the bioaerosols can be dispersed to downwind distances affecting the nearby neighboring. Therefore, in order to decrease the bioaerosols emission, doing some course of actions such as covering the surface of aeration basins, changing the aeration methods and aeration equipment (e. g using diffuser aerator) may be effective.     

The abundance of urban endotoxins as measured with an impinger-based sampling strategy

Endotoxins are components of Gram-negative bacteria with inherently high pro-inflammatory potential. In an urban environment, airborne endotoxins may associate with pollutants such as particulate matter, increasing the severity of the immune response by acting as a natural adjuvant to augment inflammatory respiratory disease development. Here, we present a closer look at outdoor urban endotoxins by applying a microbial-targeted collection strategy. Results from 87 samples distributed throughout the city of Antwerp ranged from 0.45 to 93.71 EU/m³, with a geometric mean of 4.49 EU/m³ and 95% confidence interval of 3.53–5.71 EU/m³. Sample collection was also coupled with the use of a Coulter counter, for which the particle count (2.5–10 μm/m³) showed a significant correlation with endotoxin concentration (R²?=?0.24; p?<?0.0001; n?=?64). In addition, the analysis of the cultivable bacterial colony-forming units on Reasoner’s 2A agar (expressed CFU/m³) showed to be a good indicator for airborne endotoxins (R²?=?0.57; p?<?0.0001; n?=?58). Moreover, identification of dominant bacterial colonies on these culture plates gave some indications on potential sources of these urban outdoor bacteria and endotoxins.     

A survey of the aeromycota of Sydney and its correspondence with environmental conditions: grass as a component of urban forestry could be a major determinant

A comprehensive survey of airborne fungi has been lacking for the Sydney region. This study determined the diversity and abundance of outdoor airborne fungal concentrations in urban Sydney. Monthly air samples were taken from 11 sites in central Sydney, and culturable fungi identified and quantified. The genus Cladosporium was the most frequently isolated fungal genus, with a frequency of 78 % and a mean density of 335 CFU m^?3. The next most frequently encountered genus was Alternaria, occurring in 53 % of samples with a mean of 124 CFU m^?3. Other frequently identified fungi, in decreasing occurrence, were as follows: Penicillium, Fusarium, Epicoccum, Phoma, Acremonium and Aureobasidium. Additionally, seasonal and spatial trends of airborne fungi were assessed, with increases in total culturable fungal concentrations experienced in the summer months. The correspondence between a range of key environmental variables and the phenology of airborne fungal propagules was also examined, with temperature, wind speed and proximal greenspace having the largest influence on fungal propagule density. If the greenspace was comprised of grass, stronger associations with fungal behaviour were observed.     

Comparison of dichloran rose bengal chloramphenicol and Sabouraud dextrose agar with cycloheximide and chloramphenicol for airborne mold sampling

The more the mold species isolated on a culture medium, the more the sampling environment is represented accurately. According to the sampling purpose, it is crucial to use the best culture medium for mold. However, no study is available regarding the comparison of dichloran rose bengal chloramphenicol (DRBC) and Sabouraud dextrose agar with cycloheximide and chloramphenicol (SDA-CHX-CHL) culture media in terms of their application for airborne sampling, isolation, and identification of fungi. Airborne mold samples were impacted onto both DRBC and SDA-CHX-CHL, simultaneously using single-stage Andersen sampler. The limit of detection (LOD) value for airborne mold count was 7 CFU m^?3 (1 colony growth on the Petri dish). The total mold counts (TMC) ranged between <7 and 504 CFU m^?3 (med 56 CFU m^?3) and <7 and 1218 CFU m^?3 (med 259 CFU m^?3), collected on SDA-CHX-CHL and DRBC, respectively. Significantly higher TMC were observed on DRBC than on SDA regardless of the sampling environment (i.e, indoor or outdoor) (p < 0.05). Among the most predominant mold genera, observation frequencies of Penicillium spp. and Aspergillus spp. on both culture media were found to be more than 70%. Observation frequencies of Cladosporium spp., Alternaria spp., and yeast were found to be higher in samples collected on DRBC than those on SDA-CHX-CHL. Finally, DRBC was found to be superior to SDA in terms of both number of colonies and number of genera isolated from the air.     

Diversity and characterization of airborne bacteria at two health institutions

The aim of this study was to identify the types and abundance of airborne bacteria of two health institutions (1 and 2) and to determine the genetic association between environmental and clinical isolates of Staphylococcus spp. Environmental sampling in institutions 1 and 2 was conducted for 1 year (dry and rainy seasons) using M Air T sampler. The bacteria and their susceptibility to antibiotics were identified. The colony-forming units per cubic meter (CFU/m³) of air were quantified for all the isolates, and the diversity and abundance of species were calculated. The genetic relationship between the clinical and environmental isolates of S. aureus obtained from institution 1 was established by the UPGMA based on RAPD markers. At both of the institutions, the genera most frequently isolated were Staphylococcus and Bacillus, and the greater concentration of airborne bacteria was detected during the dry season than the rainy season. The lowest diversity and highest dominance was found in the institution 2. On the other hand, at institution 1, the genus that was resistant to antibiotics was Staphylococcus, whereas at institution 2, no isolate was found to be resistant to antibiotics. Furthermore, no association between the clinical and environmental isolates of S. aureus was found. However, one clone was found in different areas of the institution 1. The presence of airborne pathogenic bacteria in institutions 1 and 2 is important to establish the measures for the prevention and control of nosocomial outbreaks.     

<Emphasis Type="Italic">Acorus calamus</Emphasis> Linn.: phytoconstituents and bactericidal property

Acorus calamus Linn. of the family Araceae (Acoraceae), commonly known as Sweet Flag and Vacha. The rhizome of this plant has medicinal properties against bugs, moths, lice and emetic stomach in dyspepsia. Chemical composition of the hydro-distilled essential oil obtained from the rhizomes of A. calamus was analyzed by gas chromatography equipped with flame ionization detector and gas chromatography coupled with mass spectrometry. The essential oil of A. calamus and its major compound β-asarone were tested against five Gram-positive, eight Gram-negative bacteria, and three fungi by the tube-dilution method at a concentration rang of 5.0–0.009 mg/mL. Forty constituents were identified which comprised 98.3 % of the total oil. The major compound β-asarone (80.6 %) was identified and confirm by NMR (¹H– & ¹³C–) in rhizome oil of A. calamus. The organism Micrococcus luteus was found to be more susceptible to the oil with minimum bactericidal concentration (MBC) value of 0.032 ± 0.004 mg/mL, followed by Aspergillus fumigatus, Aspergillus niger and Micrococcus flavus with MBC values of 0.104 ± 0.016, 0.117 ± 0.017 and 0.143 ± 0.013 mg/mL, respectively. The compound β-asarone was susceptible to the microorganism A. niger with MBC value 0.416 ± 0.065 mg/mL. The present study revealed that tetraploid variety of A. calamus is growing in this region with substantial amount of β-asarone. The oil showed bactericidal property against tested bacteria and fungi. The β-asarone exhibited poorer bactericidal activity against test microorganisms.     

First aeromycological study in an avocado agroecosystem in Mexico

Avocados (Persea americana Mill.) are economically and nutritionally valuable despite their susceptibility to several fungal diseases. This study was conducted in an agroecosystem of avocado trees in México. The air samples were collected every week by gravimetric methods at a height of 2 m from the ground level. Fungal colonies were isolated and transferred onto PDA and identified using morphological methods. During air sampling, different meteorological variables were measured. The symptoms of avocado diseases were determined by visual observations. To the best of our knowledge, this is the first study on aeromycological characterization in an avocado agroecosystem. Thirty-two airborne fungal genera were identified; Fusarium (97.2 %) and Colletotrichum (94.4 %) were the most common fungal pathogens present in the atmosphere of avocado. In addition, seven genera of important phytopathogenic fungi of other crops (Alternaria, Capnodium, Pestalotia, Stemphylium, Rhizopus, Curvularia, and Phyllachora) were isolated. The maximum concentration of total fungi was observed in June (358 CFU m^?3) and the minimum in September (83 CFU m^?3). The total fungal concentrations were significantly negatively correlated with the temperature. The symptoms of five diseases of avocado, viz. anthracnose, scab, spot, canker trunk, and vascular wilt, were identified in the area study. It was observed that the symptoms of all the above-mentioned diseases were present in June; and in the same month, the fungal concentrations were highest.     

Bacterial aerosols in an urban nursery school in Gliwice,Poland: a case study

This work presents the results of the study of airborne bacteria in a kindergarten in Gliwice, Upper Silesia, Poland. In this study, the samples of bioaerosols were collected using six-stage Andersen cascade impactor (with aerodynamic cutoff diameters 7.0, 4.7, 3.3, 2.1, 1.1, and 0.65 μm). The level of culturable bacterial aerosols indoors was about 3000 CFU m^?3—six to eight times higher than outdoors. In the classrooms, respirable bacterial particles, <4.7 µm, contributed up to 85 % of the total number of culturable bacteria, increasing the possible adverse health effects due to their inhalation. The identification of the bacterial species showing the dominance of gram-positive cocci in the indoor environment and non-sporing gram-positive rods in the outdoor air indicates that most of the bacteria present in the studied kindergarten are human origin. Using the obtained data, the nursery school exposure dose (NSED) of bioaerosols was estimated for the children and personnel of this kindergarten (nursery school). The highest value of NSED was obtained for younger children (930 CFU kg^?1) compared to older children (about 600 CFU kg^?1) and to the kindergarten staff (about 300 CFU kg^?1). This result suggests the elevated risk of adverse health effects in younger children exposed to the bioaerosols in the kindergarten, including infections.     

Phenotypic and genotypic diversity of airborne fungal spores in Demänovská Ice Cave (Low Tatras,Slovakia)

This paper is the first aero-mycological report from Demänovská Ice Cave. Fungal spores were sampled from the internal and external air of the cave in June, 2014, using the impact method with a microbiological air sampler. Airborne fungi cultured on PDA medium were identified using a combination of classical phenotypic and molecular methods. Altogether, the presence of 18 different fungal spores, belonging to 3 phyla, 9 orders and 14 genera, was detected in the air of the cave. All of them were isolated from the indoor samples, and only 9 were obtained from the outdoor samples. Overall, airborne fungal spores belonging to the genus Cladosporium dominated in this study. However, the spores of Trametes hirsuta were most commonly found in the indoor air samples of the cave and the spores of C. herbarum in the outdoor air samples. On the other hand, the spores of Alternaria abundans, Arthrinium kogelbergense, Cryptococcus curvatus, Discosia sp., Fomes fomentarius, Microdochium seminicola and T. hirsuta were discovered for the first time in the air of natural and artificial underground sites. The external air of the cave contains more culturable airborne fungal spores (755 colony-forming units (CFU) per 1 m³ of air) than the internal air (from 47 to 273 CFU in 1 m³), and these levels of airborne spore concentration do not pose a threat to the health of tourists. Probably, the specific microclimate in the cave, including the constant presence of ice caps and low temperature, as well as the location and surrounding environment, contributes to the unique species composition of aeromycota and their spores in the cave. Thus, aero-mycological monitoring of underground sites seems to be very important for their ecosystems, and it may help reduce the risk of fungal infections in humans and other mammals that may arise in particular due to climate change.     

Carbon Dioxide and Methane Fluxes From Tree Stems,Coarse Woody Debris,and Soils in an Upland Temperate Forest

Forest soils and canopies are major components of ecosystem CO₂ and CH₄ fluxes. In contrast, less is known about coarse woody debris and living tree stems, both of which function as active surfaces for CO₂ and CH₄ fluxes. We measured CO₂ and CH₄ fluxes from soils, coarse woody debris, and tree stems over the growing season in an upland temperate forest. Soils were CO₂ sources (4.58 ± 2.46 µmol m^?2 s^?1, mean ± 1 SD) and net sinks of CH₄ (?2.17 ± 1.60 nmol m^?2 s^?1). Coarse woody debris was a CO₂ source (4.23 ± 3.42 µmol m^?2 s^?1) and net CH₄ sink, but with large uncertainty (?0.27 ± 1.04 nmol m^?2 s^?1) and with substantial differences depending on wood decay status. Stems were CO₂ sources (1.93 ± 1.63 µmol m^?2 s^?1), but also net CH₄ sources (up to 0.98 nmol m^?2 s^?1), with a mean of 0.11 ± 0.21 nmol m^?2 s^?1 and significant differences depending on tree species. Stems of N. sylvatica, F. grandifolia, and L. tulipifera consistently emitted CH₄, whereas stems of A. rubrum, B. lenta, and Q. spp. were intermittent sources. Coarse woody debris and stems accounted for 35% of total measured CO₂ fluxes, whereas CH₄ emissions from living stems offset net soil and CWD CH₄ uptake by 3.5%. Our results demonstrate the importance of CH₄ emissions from living stems in upland forests and the need to consider multiple forest components to understand and interpret ecosystem CO₂ and CH₄ dynamics.     

Enhancement of electricity production in a mediatorless air–cathode microbial fuel cell using <Emphasis Type="Italic">Klebsiella</Emphasis> sp. IR21

A novel dissimilatory iron-reducing bacteria, Klebsiella sp. IR21, was isolated from the anode biofilm of an MFC reactor. Klebsiella sp. IR21 reduced 27.8 % of ferric iron to ferrous iron demonstrating that Klebsiella sp. IR21 has electron transfer ability. Additionally, Klebsiella sp. IR21 generated electricity forming a biofilm on the anode surface. When a pure culture of Klebsiella sp. IR21 was supplied into a single chamber, air–cathode MFC fed with a mixture of glucose and acetate (500 mg L^?1 COD), 40–60 mV of voltage (17–26 mA m^?2 of current density) was produced. Klebsiella sp. IR21 was also utilized as a biocatalyst to improve the electrical performance of a conventional MFC reactor. A single chamber, air–cathode MFC was fed with reject wastewater (10,000 mg L^?1 COD) from a H₂ fermentation reactor. The average voltage, current density, and power density were 142.9 ± 25.74 mV, 60.5 ± 11.61 mA m^?2, and 8.9 ± 3.65 mW m^?2, respectively, in the MFC without inoculation of Klebsiella sp. IR21. However, these electrical performances of the MFC were significantly increased to 204.7 ± 40.24 mV, 87.5 ± 17.20 mA m^?2, and 18.6 ± 7.23 mW m^?2, respectively, with inoculation of Klebsiella sp. IR21. The results indicate that Klebsiella sp. IR21 can be utilized as a biocatalyst for enhancement of electrical performance in MFC systems.     

Percentage cover,biomass, distribution,and potential habitat mapping of natural macroalgae,based on high-resolution satellite data and in situ monitoring,at Libukang Island,Malasoro Bay,Indonesia

In this study, we combined remote sensing data and in situ observations to explore the potential habitats of macroalgae at Libukang Island, Indonesia. High-resolution satellite images from the GeoEye-1 were used to estimate and to map the geomorphological structures together with macroalgal species in the study area. Seasonal variations of percentage cover and biomass of macroalgae associated with substrates were investigated in May and November 2014, and June 2015, using quadrats as sampling unit. A total of nine common genera were found in the study area with three dominant genera: Sargassum, Padina, and Turbinaria. Most of macroalgae was observed in the eastern part of the Island, on several substrate types and particular oceanographic conditions (wave and current). Mean biomasses of Sargassum and Padina were high in May (1189.6 ± 455 and 166.7 ± 15.4 g DW.m^?2, respectively), while the biomass of Turbinaria was high in November (3245 ± 599.8 g DW.m^?2). The map accuracy of image classification for all typology substrates was 74.19%. Overall, approximately 62.3% of the total study area can be considered as potential for natural macroalgae habitats. Spectral response characteristic of shallow water substrates at study area based on GeoEye-1 is also presented. The results of this study exhibit a potential utilization of natural macroalgae in the study area, and provide information for a possible diversification of the use of macroalgae in Indonesia. The method could be useful for habitat management and future biomonitoring in the study area or other similar areas in Indonesia.     

Productivity and biochemical composition of <Emphasis Type="Italic">Tetradesmus obliquus</Emphasis> and <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis>: effects of different cultivation approaches

The present work evaluated biomass productivity, carbon dioxide fixation rate, and biochemical composition of two microalgal species, Phaeodactylum tricornutum (Bacillariophyta) and Tetradesmus obliquus (Chlorophyta), cultivated indoors in high-technology photobioreactors (HT-PBR) and outdoors both in pilot ponds and low-technology photobioreactors in a greenhouse in southern Italy. Microalgae were grown in standard media, under nitrogen starvation, and in two liquid digestates obtained from anaerobic digestion of agro-zootechnical and vegetable biomass. P. tricornutum, cultivated in semi-continuous mode in indoor HT-PBRs with standard medium, showed a biomass productivity of 21.0?±?2.3 g m^?2 d^?1. Applying nitrogen starvation, the lipid productivity increased from 2.3 up to 4.5?±?0.5 g m^?2 d^?1, with a 24 % decrease of biomass productivity. For T. obliquus, a biomass productivity of 9.1?±?0.9 g m^?2 d^?1 in indoor HT-PBR was obtained using standard medium. Applying liquid digestates as fertilizers in open ponds, T. obliquus gave a biomass productivity (10.8?±?2.0 g m^?2 d^?1) not statistically different from complete medium such as P. tricornutum (6.5?±?2.2 g m^?2 d^?1). The biochemical data showed that the fatty acid composition of the microalgal biomass was affected by the different cultivation conditions for both microalgae. In conclusion, it was found that the microalgal productivity in standard medium was about doubled in HT-PBR compared to open ponds for P. tricornutum and was about 20 % higher for T. obliquus.     

Diversity of culturable bacterial communities in the intestinal tracts of goldfish (<Emphasis Type="Italic">Carassius auratus</Emphasis>) and their ability to produce <Emphasis Type="Italic">N</Emphasis>-acyl homoserine lactone

Intestinal bacteria isolated from goldfish (Carassius auratus) were identified based on 16 ribosomal RNA (rRNA) gene sequences and screened for their ability to produce N-acyl homoserine lactone (AHL), an autoinducer of the quorum sensing (QS) system. The 230 aerobes/facultative anaerobes that were isolated comprised members of the genera Aeromonas (184 isolates), Citrobacter (11), Enterobacter (2), Shewanella (28), Vagococcus (1), and Vibrio (4). Among these genera, the two most abundant species were Aeromonas veronii (163 isolates) and Shewanella xiamenensis (27). In addition, 142 obligate anaerobes consisting of Cetobacterium somerae (139 isolates), Clostridium frigidicarnis (2), and Cetobacterium sp. (1) were also isolated. One hundred seventy isolates (74.2%) belonging to the genera Aeromonas, Citrobacter, Enterobacter, Shewanella, and Vibrio produced AHL, while 155 (67.7%) and 91 (39.7%) isolates possessed the luxR and luxI gene homologs, respectively. None of the obligate anaerobes produced AHL or possessed luxRI homologs. Total viable counts ranged from 1.2 × 10⁷ to 2.2 × 10⁹ CFU/g, which were accounted for 0.8 to 15.2% of direct counts. Aeromonas veronii, S. xiamenensis, and C. somerae were detected from five goldfish at densities ranging from 4.0 × 10⁶ to 1.7 × 10⁹ CFU/g, indicating that these bacteria are dominant components of the culturable gut flora in goldfish. In addition, members of the genera Aeromonas and Shewanella appeared to communicate with each other by using the QS system to some extent when the concentration of AHL reaches a certain threshold. It is therefore suggested that bacteria with the ability to disrupt AHL secretion in intestinal environments are potential candidates for probionts for preventing opportunistic infections in freshwater fish such as goldfish.     

Cloning,expression, and characterization of a thermostable glucose-6-phosphate dehydrogenase from <Emphasis Type="Italic">Thermoanaerobacter tengcongensis</Emphasis>

Glucose-6-phosphate dehydrogenases (G6PDs) are important enzymes widely used in bioassay and biocatalysis. In this study, we reported the cloning, expression, and enzymatic characterization of G6PDs from the thermophilic bacterium Thermoanaerobacter tengcongensis MB4 (TtG6PD). SDS-PAGE showed that purified recombinant enzyme had an apparent subunit molecular weight of 60 kDa. Kinetics assay indicated that TtG6PD preferred NADP⁺ (k _cat/K _m = 2618 mM^?1 s^?1, k _cat = 249 s^?1, K _m = 0.10 ± 0.01 mM) as cofactor, although NAD⁺ (k _cat/K _m = 138 mM^?1 s^?1, k _cat = 604 s^?1, K _m = 4.37 ± 0.56 mM) could also be accepted. The K _m values of glucose-6-phosphate were 0.27 ± 0.07 mM and 5.08 ± 0.68 mM with NADP⁺ and NAD⁺ as cofactors, respectively. The enzyme displayed its optimum activity at pH 6.8–9.0 for NADP⁺ and at pH 7.0–8.6 for NAD⁺ while the optimal temperature was 80 °C for NADP⁺ and 70 °C for NAD⁺. This was the first observation that the NADP⁺-linked optimal temperature of a dual coenzyme-specific G6PD was higher than the NAD⁺-linked and growth (75 °C) optimal temperature, which suggested G6PD might contribute to the thermal resistance of a bacterium. The potential of TtG6PD to measure the activity of another thermophilic enzyme was demonstrated by the coupled assays for a thermophilic glucokinase.     

Rapid Detection Device for <Emphasis Type="Italic">Salmonella typhi</Emphasis> in Milk,Juice, Water and Calf Serum

A limit of detection of 200 CFU/mL of Salmonella typhi spiked in various sample matrices were achieved in 30 min. The sample matrices were raw/unprocessed milk, commercially available milk, juice from packed bottles, fresh juice from carts, potable water, turbid water and calf serum. The complete protocol comprised of three steps: (a) cell lysis (b) nucleic acid amplification and (c) an in situ optical detection. The cell lysis was carried out using a simple heating based protocol, while the loop-mediated isothermal amplification of DNA was carried out by an in-house designed and fabricated system. The developed system consists of an aluminum block fitted with two cartridge heaters along with a thermocouple. The system was coupled to a light source and spectrometer for a simultaneous in situ detection. Primers specific for STY2879 gene were used to amplify the nucleic acid sequence, isolated from S. typhi cells. The protocol involves 15 min of cell lysis and DNA isolation followed by 15 min for isothermal amplification and simultaneous detection. No cross-reactivity of the primers were observed at 10⁶ CFU/mL of Escherichia coli, Vibrio cholerae, Salmonella typhimurium, Salmonella paratyphi A, Pseudomonas aeruginosa, Bacillus cereus, Lysteria monocytogenes, Clostridium botulinum, Staphylococcus aureus and Salmonella havana. In addition, the system was able to detect S. typhi of 200 CFU/mL in a concoction of 10⁶ CFU/mL of E. coli, 10⁶ CFU/mL of V. cholerae, and 10⁶ CFU/mL of hepatocyte-derived cellular carcinoma HUH7 cells. The proposed rapid diagnostic system shows a promising future in the field of food and medical diagnostics.     

First volumetric record of fungal spores in the atmosphere of Montevideo City,Uruguay: a 2-year survey

In Uruguay, aeromycological studies are restricted to a gravimetric analysis performed from December 1942 to March 1944 in Montevideo where spores of Pucciniaceae, Alternaria and Helminthosporium were the only specimens identified. Daily monitoring of airborne fungal spores was carried out for the first time in Montevideo, from April 2012 to March 2014, using a Rotorod sampler in order to evaluate the seasonal variation and influence of meteorological parameters. A total of 548,309.68 spores/m³ were recorded which belong to anamorphs of Higher Fungi (69.18 %), Phyla Ascomycota (12.62 %), Basidiomycota (8.01 %), Oomycota (0.37 %) and Myxomycota (0.06 %). Airborne spores occurred in Montevideo throughout the whole year. However, a seasonal pattern was revealed, with the highest concentrations recorded in autumn and summer. The most abundant spore types were Cladosporium (53.22 %), Alternaria (6.62 %), Didymella Group (5.86 %), Leptosphaeria Group (4.37 %) and Coprinus (4.3 %). Temperature appeared to be the most influential meteorological factor correlating significantly and positively with total spore, Cladosporium, Alternaria and Didymella Group abundance. Relative humidity influenced positively total spore, Cladosporium and Didymella Group concentrations while a weak negative association was obtained for Alternaria. Wind speed correlated negatively with total spore, Cladosporium, Alternaria and Didymella Group. Precipitation showed a negative influence on Alternaria, while positive correlations were observed for Didymella Group. For the first time, fungal spores considered allergenic were recorded in Montevideo atmosphere and the risk of exposure would have been high from December to June. However, long-term sampling is needed to define seasonal prevalence patterns and the influence of meteorological conditions on spore abundance.     

Atmospheric concentrations and intradiurnal pattern of <Emphasis Type="Italic">Alternaria</Emphasis> and <Emphasis Type="Italic">Cladosporium</Emphasis> conidia in Tétouan (NW of Morocco)

Fungal spores of Alternaria and Cladosporium are ubiquitous components of both indoor and outdoor air samples and are the main causes of human respiratory allergies. Monitoring these airborne fungal spores during 2009–2014 was carried out by means of Hirst-type spore trap to investigate their airborne spore concentrations with respect to annual load, seasonality and overall intradiurnal pattern. Alternaria and Cladosporium spores are present throughout the year in the atmosphere of Tétouan, although they show seasonal variations. Despite important differences between years, their highest levels presented a first peak during spring and a higher second peak in summer or autumn depending on the year. The spore concentrations were homogeneously distributed throughout the day with slight increase of 7.6 and 3.7% on average between 12–14 and 14–16 h for Alternaria and Cladosporium, respectively. The borderline of 3000 sp/m³ of Cladosporium linked to the occurrence of allergic diseases was exceeded between 13 and 31 days. Airborne spores of Alternaria overcame the threshold value of 100 sp/m³ up to 95 days, suggesting that Cladosporium and Alternaria could be clinically significant aeroallergens for atopic patients.     

Species and Genotype Effects of Bioenergy Crops on Root Production,Carbon and Nitrogen in Temperate Agricultural Soil

Bioenergy crops have a secondary benefit if they increase soil organic C (SOC) stocks through capture and allocation below-ground. The effects of four genotypes of short-rotation coppice willow (Salix spp., ‘Terra Nova’ and ‘Tora’) and Miscanthus (M.?×?giganteus (‘Giganteus’) and M. sinensis (‘Sinensis’)) on roots, SOC and total nitrogen (TN) were quantified to test whether below-ground biomass controls SOC and TN dynamics. Soil cores were collected under (‘plant’) and between plants (‘gap’) in a field experiment on a temperate agricultural silty clay loam after 4 and 6 years’ management. Root density was greater under Miscanthus for plant (up to 15.5 kg m^?3) compared with gap (up to 2.7 kg m^?3), whereas willow had lower densities (up to 3.7 kg m^?3). Over 2 years, SOC increased below 0.2 m depth from 7.1 to 8.5 kg m^?3 and was greatest under Sinensis at 0–0.1 m depth (24.8 kg m^?3). Miscanthus-derived SOC, based on stable isotope analysis, was greater under plant (11.6 kg m^?3) than gap (3.1 kg m^?3) for Sinensis. Estimated SOC stock change rates over the 2-year period to 1-m depth were 6.4 for Terra Nova, 7.4 for Tora, 3.1 for Giganteus and 8.8 Mg ha^?1 year^?1 for Sinensis. Rates of change of TN were much less. That SOC matched root mass down the profile, particularly under Miscanthus, indicated that perennial root systems are an important contributor. Willow and Miscanthus offer both biomass production and C sequestration when planted in arable soil.     

Optimization of continuous-flow solid-phase denitrification via coupling carriers in enhancing simultaneous removal of nitrogen and organics for agricultural runoff purification

Coupling of biodegradable corncob and plastic carrier was optimized in continuous-flow solid-phase denitrification systems for enhancing simultaneously removal of nitrogen and organics in agricultural runoff. In compared with preposition of plastic carriers and mixed distribution method, it was demonstrated that the preposition of corncobs simultaneously enhanced nitrate (6.64 ± 1.35 mg L^?1 day ^?1) and organics removal (6.33 ± 1.44 mg L^?1 day^?1) at a hydraulic retention time (HRT) of 6 h. The operation performance could be further enhanced with extension of HRT to 12 h. The dominant genera found in corncob were denitrifiers for nitrate reduction (Bosea, Simplicispira, Desulfovibrio, Klebsiella, etc.) and fermentative bacteria (Pleomorphomonas, Actinotalea, Opitutus, Cellulomonas, Bacteroides, etc.) responsible for corncob degrading to simple organics for other denitrifiers. However, much lower and different denitrifiers abundances (Bradyrhizobium, Acinetobacter, Bacillus, etc.) exhibited on plastic filler than those of corncob. It well explained that the biofilm on plastic carrier was mainly related with organics removal while the biofilm on corncobs inclined to effectively remove nitrate, and simultaneous removal of nitrogen and organics could be achieved in coupling carriers system with preposition of biodegradable corncob.