Biological activities of endozoic fungi isolated from Biomphalaria alexandrina snails maintained in different environmental conditions

This work aims at studying Biomphalaria alexandrina snails as a source of bioactive compounds. Adult snails were maintained in plastic, mud and cement matrices. Three groups were prepared; under normal laboratory conditions, in slightly low pH conditions, and in high temperature (30°C) conditions. Nine fungal species were isolated from soft tissues of snails. Ethyl acetate and acetone extracts were prepared from each fungal species, and their biological activities were investigated. Paecilomyces variotii extracts were the most effective as antimicrobial agents, while acetone extract of Trichoderma harzianum showed high antioxidant activity. Acetone extracts of Penicillium islandicum and Aspergillus niger were highly active against hepatocellular carcinoma (HepG2) cell lines. Gas chromatography/mass spectrometry analysis of the five effective extracts showed the presence of various compounds. B. alexandrina snails may be regarded as a newly discovered source of beneficial compounds through the metabolites produced by their endozoic fungal strains.     

The effects of an industrial waste (cryolite recovery sludge) upon the atlantic Salmon, Salmo Salar (l.) detection thresholds and the effects of exposure to the waste upon detection of an amino acid

Thresholds for detection of cryolite recovery sludge (CRS, an aluminium smelter waste dumped at sea) were determined for salmon. Salmo salar (L.). in sea water using a cardiac conditioning technique. Some effects of exposure of salmon to CRS filtrate (mean concentration 5.5°_D) for up to 1 h were monitored. Oxygen consumption and ventilation rate increased and heart rate decreased after presentation of the filtrate. The effects were transient and the physiological parameters monitored returned to pre-exposure levels within 2 h of ceasing filtrate presentation. Detection levels for an amino acid (glycine) were determined for salmon in sea-water before and after exposure to CRS filtrate (mean concentration 5.5%). Within 24 h of exposure to the CRS filtrate the mean threshold level was significantly different from the pre-exposure detection level. However, 24–48 h after exposure the threshold for detection of glycine was no longer significantly different.     

The usefulness of Lymnaea stagnalis L. as a biological indicator in toxicological bio-assays (model substance α-HCH)

Short- and long-term studies with α-hexachlorocyclohexane (α-HCH) were carried out on the pond snail (Lymnaea stagnalis L.), to test the usefulness of this organism as a biological indicator of pollutants in surface water.Based on mortality and immobilization in the short-term study (2 days) an ec₅₀-value of 1200 μg α-HCH 1⁻¹ could be determined.In the long-term study (70 days) an inverse time-independent relation was found between egg production rate (= number of eggs produced per unit of time) and the α-HCH concentration in the water. Based on this egg production inhibition an EC⁵⁰ of 250 μg α-HCH 1⁻¹ could be determined. The percentage of fertilized eggs per capsule was not affected. No morphological abnormalities were noticed during the embryonic development, although a significantly dose-related delay occurred with respect to the hatching of the eggs. Based on the number of eggs which did not hatch, a lc₅₀ of 230 μg α-HCH 1⁻¹ could be determined. The combination of (1) the inhibition of the egg-production of the adult snails (caused by a significant prolongation of the oviposition interval and by a significant decrease of the number of eggs per capsule) and (2) the mortality of the young during their development caused a 50° reduction of the overall reproductivity at 65 μg α-HCH 1⁻¹. The heart-rate of newborn snails was slowed significantly by α-HCH. Replacing the snails into an α-HCH-free medium for 16 days, after a 40-day exposure to α-HCH, did not result in the disappearance of the effects mentioned above.The susceptibility of Lymnaea stagnalis to α-HCH did not differ much from that of Daphnia magna (a crustacean). This organism proved to be the most sensitive one of all tested organisms (Chlorella, Daphnia, Lebistes, Salmo) in previous studies with α-HCH. Therefore Lymnaea stagnalis might be useful as a test organism in future environmental toxicity studies, although these kinds of experiments have to be considered as very laborious and costly.     

Volatile organic compounds emitted by filamentous fungi isolated from flooded homes after Hurricane Sandy show toxicity in a Drosophila bioassay

Superstorm Sandy provided an opportunity to study filamentous fungi (molds) associated with winter storm damage. We collected 36 morphologically distinct fungal isolates from flooded buildings. By combining traditional morphological and cultural characters with an analysis of ITS sequences (the fungal DNA barcode), we identified 24 fungal species that belong to eight genera: Penicillium (11 species), Fusarium (four species), Aspergillus (three species), Trichoderma (two species), and one species each of Metarhizium, Mucor, Pestalotiopsis, and Umbelopsis. Then, we used a Drosophila larval assay to assess possible toxicity of volatile organic compounds (VOCs) emitted by these molds. When cultured in a shared atmosphere with growing cultures of molds isolated after Hurricane Sandy, larval toxicity ranged from 15 to 80%. VOCs from Aspergillus niger 129B were the most toxic yielding 80% mortality to Drosophila after 12 days. The VOCs from Trichoderma longibrachiatum 117, Mucor racemosus 138a, and Metarhizium anisopliae 124 were relatively non‐toxigenic. A preliminary analysis of VOCs was conducted using solid‐phase microextraction‐gas chromatography‐mass spectrometry from two of the most toxic, two of the least toxic, and two species of intermediate toxicity. The more toxic molds produced higher concentrations of 1‐octen‐3‐ol, 3‐octanone, 3‐octanol, 2‐octen‐1‐ol, and 2‐nonanone; while the less toxic molds produced more 3‐methyl‐1‐butanol and 2‐methyl‐1‐propanol, or an overall lower amount of volatiles. Our data support the hypothesis that at certain concentrations, some VOCs emitted by indoor molds are toxigenic.     

Enhancement of Nitrobacter activity by heterotrophic bacteria

The present work shows that a supply which is not sterile and which contains organic matter does not interfere with the performance of a column filled with a support previously inoculated with Nitrobacter winogradskyi serotype agilis.Measurements of oxidation rates give results higher than those obtained under axenic conditions (maximum oxidation rate: 220 mg NO₂⁻ h⁻¹ l⁻¹ of reactor volume under non-sterile conditions: 160 mg NO₂⁻ h⁻¹ l⁻¹ of reactor volume under axenic conditions).This finding has concentrated our work on the effect of heterotrophic bacteria and of organic matter on the growth of Nitrobacter. We show that a fermentation filtrate of a heterotrophic bacterium (Pseudomonas sp.) added to a fermenter culture of Nitrobacter produces an increase of activity. Experimental results indicate an appreciable reduction in the latence period (15-0 h) and a considerable increase in the rate of growth of Nitrobacter. (Maximum growth rate with 10% of heterotrophic filtrate: 0.044 h⁻¹; without filtrate: 0.032 h⁻¹.)     

Effect of exhaust gas recirculation on a nanoparticle-doped biodiesel- and diesel-blends-fuelled diesel engine

ABSTRACT

This work investigates the effect of adding Cerium oxide nanoparticles at different proportions (30, 60 and 90?ppm) to Calophyllum inophyllum methyl ester and diesel blends (20% CI methyl ester and 80% diesel) in a four-stroke single-cylinder diesel engine. Addition of nanoparticles is a strategy to reduce emission and to improve the performance of the biodiesel. Modified fuels are introduced into the engine by admitting exhaust gas recirculation (EGR) at a rate of 10% and 20% so as to reduce nitrogen oxide (NO_X) emissions from biodiesel and diesel blends. Results revealed a significant reduction in emissions (CO, NO_X, HC and Smoke) at a 10% EGR rate. However, brake thermal efficiency is reduced with an increase in brake-specific fuel consumption at higher EGR rates. Hence, it is observed that 10% EGR rate is an effective method to control the emission of biodiesel and diesel blends without compromising much on engine efficiency.     

Laboratory-based investigation of the materials’ water activity and pH relative to fungal growth in internally insulated solid masonry walls

This project investigated fungal growth conditions in artificially contaminated interfaces between solid masonry and adhesive mortar for internal insulation. The project comprised several laboratory experiments: test of three fungal decontamination methods; investigation of development of fungal growth in solid masonry walls fitted with five internal insulation systems; and investigation of volatile organic compounds (VOC) diffusion through materials and whole insulation systems. One aim was to examine whether the alkaline environment (pH > 9) in the adhesive mortars could prevent fungal growth despite the water activity (a_w) in the interface exceeds the level (a_w > 0.75) commonly considered critical for fungal growth. The findings indicate that do-it-yourself decontamination solutions were inadequate for removal of fungal growth, while professional solutions were successful. However, the choice of decontamination method was of minor importance in the case of application of internal insulation with high pH adhesive mortar, as the high pH adhesive mortars were found to inactivate existing growth and prevented spore germination during the experimental period. The three tested VOCs were capable of diffusing through most of the examined products and could potentially affect the indoor air quality.     

Effect of exhaust gas recirculation on performance and emission characteristics of a diesel engine fuelled with tamarind biodiesel

The present research work focuses on the influence of exhaust gas recirculation (EGR) on the characteristics of the diesel engine operated with 20% tamarind seed methyl ester (TSME 20) as the renewable fuel. The use of TSME 20 as biodiesel results in closer performance characteristics with diesel fuel. However, TSME 20 biodiesel blend generated higher oxides of nitrogen (NO_X) emissions at all operating conditions. Firstly, tests are performed using diesel and TSME 20 biodiesel blend at constant speed under different loads. Thereafter, experiments are conducted on TSME 20 with EGR rates at different concentrations. The test results revealed that with TSME 20 with 20% EGR rate, NO_X emissions are reduced by 45.67% and 52.69% when compared to diesel and TSME 20. However, there is a slight reduction in brake thermal efficiency. Hence, the use of 20% EGR rate to TSME 20 is an optimum approach for better control of NO_X emissions.

Abbreviations BDC: bottom dead centre; BMEP: brake mean effective pressure; BSFC: brake-specific fuel consumption; BTE: brake thermal efficiency; CO: carbon monoxide; CO₂: carbon dioxide; EGR: exhaust gas recirculation; FSN: filter smoke number; HC: hydrocarbon; kWh: kilo Watt hour; NO_X: oxides of nitrogen; ppm: parts per million; SO: smoke opacity; TDC: top dead centre; TSME: tamarind seed methyl ester; TSME 20: 20% tamarind seed methyl ester; TSME 20–20%: tamarind seed methyl ester with 80% diesel; TSME 10% EGR: TSME 20 with 10% exhaust gas recirculation; TSME 20% EGR: TSME 20 with 20% exhaust gas recirculation; TSME 30% EGR: TSME 20 with 30% exhaust gas recirculation     

Biodegradation of low density polyethylene (LDPE) by certain indigenous bacteria and fungi

Low-density polyethylene (LDPE) is an environmental problem because it is discarded randomly, and because in dumpsites, it does not readily degrade. This study reports evidence of successful biodegradation by two fungal species (Aspergillus flavus MCP₅ and Aspergillus flavus MMP₁₀) and eight bacterial species (Acinetobacter sp. MGP₁, Bacillus sp. MGP₁, Pseudomonas sp. MMP₁, Bacillus sp. MMP₅, Staphylococcus sp. MMP₁₀, Bacillus sp. MGP₁, Micrococcus sp. MMP₅ and Bacillus sp. MMP₁₀). These were demonstrated to have used LDPE as both nitrogen and carbon source. LDPE-users were then characterised and identified using standard microbiological procedures. Biodegradation study was done using selected bacterial and fungal isolates, singly and in consortia, to degrade heat-sterilised ground LDPE in media devoid of carbon source, and carbon and nitrogen source. Biodegradation was monitored using gravimetric methods and Fourier transform infrared spectroscopy. This study revealed some microorganisms can use LDPE as both nitrogen and carbon source in the absence of additives.     

Acoustic wave velocity and permeability evolution during pressure cycles on a thermally cracked granite

Compressional waves velocity V_P and water permeability K were measured during long-term experiments in a high-pressure vessel (in the range 11–75 MPa for confining pressures and 10–70 MPa for pore pressures). Experiments were carried out on fractured granite specimens prepared by a controlled heating treatment at 510°C, which generated thermal cracks. A distinct effective pressure law was derived from the measurements within specific [P_C; P_P] ranges, for each of these properties. Data analysis emphasizes the differences in V_P and K evolution during pressure cycles. V_P shows a regular increase during effective pressure increase; but some ‘crack lips sticking’ is thought to be responsible for the hysteresis found during the first stages of effective pressure decrease. K decreases exponentially with effective pressure increase, whereas during effective pressure decrease K values are systematically lower, which attest to irreversible changes in the connected crack network likely to be the result of irreversible crack closure of a subset of cracks. Such study of the simultaneous evolution of physical properties of the rocks as a function of the applied stresses is relevant for man-induced applications like radioactive waste disposal where perturbations of the environmental stresses may modify the rock structure, thus leading to changes in mechanical or transport properties of the host rock.     

Bioaccumulation of arsenic in aquatic plants and animals near a municipal landfill

This study was conducted to assess the water quality and arsenic (As) concentrations in water, sediment, aquatic plants and animals near a municipal landfill. The As concentration in the samples was analysed using inductively coupled plasma optical emission spectrometry. Thirty-six aquatic plants of four species were collected. The highest As concentration was found in Limnocharis flava (0.78 ± 0.31 mg/kg). The aquatic animals included 31 fish of four species and 27 freshwater snails of three species. The highest As concentrations in the fish and freshwater snails were found in Oreochromis niloticus (0.16 ± 0.16 mg/kg) and Filopaludina sumatrensis (0.18 ± 0.06 mg/kg), respectively. The highest bioaccumulation factor of As in the aquatic plants, fish and freshwater snails were found in L. flava (131.30 ± 15.35), O. niloticus (228.21 ± 26.99) and F. sumatrensis (33.04 ± 10.58), respectively. Since the accumulation of As was higher in the sediment than in the water, aquatic plants and animals took up As directly from the environment, resulting in As accumulation in the aquatic food web.     

Concentration of viruses from water on bituminous coal

The potential of bituminous coal for adsorption of viruses, using poliovirus as a model, was investigated. Influence of pH of water on the adsorption of viruses on a coal bed with and without addition of cation (Al³⁺) indicated that poliovirus could be adsorbed efficiently at pH 5 in presence of AlCl₃ at a concentration of 0.0005 M. Studies on the effect of different concentrations of monovalent, divalent and trivalent cations showed that the trivalent cation was more effective and was required at a lower concentration than other cations tested. A coal bed of 1.5 g could adsorb as high as 204,000 PFU from water based on the absence of virus in the filtrate. Total organic carbon content (TOC, 21–51 mg 1⁻¹) of the water did not interfere in virus adsorption to coal. The results obtained indicated that a bituminous coal bed could be used as one of the methods for efficient concentration of viruses from water.     

Examination of Mechanisms Responsible for Organic Dust-Related Diseases: Mediator Release Induced by Microorganisms. A Review

Microbial content in dusts such as bacteria, endotoxins and fungal spores are thought to be important causative agents for the symptoms in organic dust-related diseases. Micro-organism-induced mediator release was therefore examined in human cells. Bacteria were found to trigger the release of histamine and leurotriene B₄ from bronchoalveolar cells, and in suspensions of dispersed lung and tonsillar cells they induce the release of histamine and prostaglandin D₂. Basophil histamine release was triggered by both bacteria and their endotxins. Furthermore, histamine release caused by allergic as well as non-allergic reactions was enhanced by bacteria, endotoxins and fungal spores of mould. These effects of dust components may be crucial for the symptoms in q a n i c dust-related diseases, since the mediators are of key importance to the broncho-obstructive and inflammatory events in these disorders.     

Methyl chloride as a gas-tracer for measuring stream reaeration coefficients—II: Stream studies

A method is described for measuring stream reaeration rate coefficients using methyl chloride as a gas-tracer. Methyl chloride is a stable tracer that is capable of being determined to a lower detection limit of 1 × 10⁻¹² g by a gas chromatographic technique. Laboratory studies are reported, in which k₂ and the analogous transfer coefficient for methyl chloride, k_CH3Cl, are measured simultaneously at different temperatures in the range 5–35°C. The laboratory results indicate a temperature dependence for the transfer coefficient ratio, , fitted empirically to an expression based upon the absolute rate model for diffusion giving where T is the absolute temperature.     

Comparative effectiveness of chlorine and chlorine dioxide biocide regimes for biofouling control

The effectiveness of chlorine (Cl₂) and chlorine dioxide (ClO₂) in controlling biofouling of 304L stainless steel heat exchanger tubing was compared using an experimental trough system. Three combinations of dose and contact time were evaluated. Chlorination coupled with a dispersant was also tested. Three criteria were used to assess the degree of fouling; organic carbon and dry weight of the fouling material accumulated on metal specimens and the visual appearance of this material on the specimens. These parameters correlated well with one another and therefore, collectively provided an effective means of evaluating biocide efficacy.Metal specimens in all troughs receiving biocide treatment were much less fouled than those in the trough receiving no biocide. Continuous application of Cl₂ at about 0.15 ppm was more effective than four 15-min 1 ppm Cl₂ applications per day. Both of these treatment regimes were more effective than a dose of about 1 ppm for 1 h day⁻¹. Use of a dispersant in combination with Cl₂ showed no significant reduction in the amount of biofouling material accumulation, although a difference in the texture of this material was observed. Unlike the Cl₂ results, low-level continuous ClO₂ treatment at 0.15 ppm resulted in biofouling similar to that when 1 ppm of ClO₂ was used for 1 h day⁻¹. Overall, ClO₂ was significantly (P < 0.05) more effective in controlling biofouling than Cl₂.     

Investigation of bacterial and fungal communities in indoor and outdoor air of elementary school classrooms by 16S rRNA gene and ITS region sequencing

The advent of high-throughput sequencing methods allowed researchers to fully characterize microbial community in environmental samples, which is crucial to better understand their health effects upon exposures. In our study, we investigated bacterial and fungal community in indoor and outdoor air of nine classrooms in three elementary schools in Seoul, Korea. The extracted bacterial 16S rRNA gene and fungal ITS regions were sequenced, and their taxa were identified. Quantitative polymerase chain reaction for total bacteria DNA was also performed. The bacterial community was richer in outdoor air than classroom air, whereas fungal diversity was similar indoors and outdoors. Bacteria such as Enhydrobacter, Micrococcus, and Staphylococcus that are generally found in human skin, mucous membrane, and intestine were found in great abundance. For fungi, Cladosporium, Clitocybe, and Daedaleopsis were the most abundant genera in classroom air and mostly related to outdoor plants. Bacterial community composition in classroom air was similar among all classrooms but differed from that in outdoor air. However, indoor and outdoor fungal community compositions were similar for the same school but different among schools. Our study indicated the main source of airborne bacteria in classrooms was likely human occupants; however, classroom airborne fungi most likely originated from outdoors.     

A quantitative investigation of the reaction of ozone with p-toluenesulfonic acid in aqueous solution as a model compound for anionic detergents

The reaction of ozone with p-toluenesulfonic acid (PTA) at initial pH 3 and 12 in aqueous solutions (25°C) has been studied at initial concentration 1 mmol l⁻¹ and ozone dose is 24 mg min⁻¹ 1. and 11 mg min⁻¹ 1. respectively. The substrate elimination follow a zero order rate law. A 98% p-toluenesulfonic acid reduction requires at least 7 mol O₃ per mol PTA, however to remove 100% PTA the consumption of ozone increases to 16 mmol O₃ per mmol PTA. At this point a 28% reduction of DOC and a 74% COD reduction was achieved.The PTA decomposition is quicker at higher ozone flow rate, but the specific ozone consumption increases also. As oxidation products the following compounds were identified and their quantitative variations as function of ozonation time were measured: methylglyoxal, acetic acid, formic acid, pyruvic acid, oxalic acid, H₂SO₄ and H₂O₂. As byproduct mesoxalic acid was identified. At pH 12 lactic acid as a further oxidation product was observed.Balances of carbon, sulfur and methyl as well of the acid equivalents indicate one or more intermediates with a sulfonic acid group. These intermediates with a proportion of about 20% disappear after 100% PTA elimination. On account of these results a reaction mechanism is discussed.     

Mould Allergy in Schoolchildren in Relation to Airborne Fungi and Residential Characteristics in Homes and Schools in Northern Norway

Abstract During winter, airborne microfungi were collected from the homes and schools of 19 children sensitized to house dust mites (HDM) and 19 non-atopic control children in the community of Sør-Varanger, northern Norway. The samples were cultivated and microfungal growth was identified microscopically. Indoor humidity, temperature, carbon dioxide (CO₂), allergic symptoms and sensitization were registered. Symptom data and information concerning sociodemographic and housing conditions were obtained using a questionnaire. Penicillium was the most common microfungus in both homes and schools, followed by different yeasts, Aspergillus, Cladosporium and Mucor. The number of infected homes was equal in the HDM-sensitized and in the control group, but the mean aerospore counts were higher in the HDM-sensitized than in the control group. The lowest aerospore counts were found in the schools. High airborne spore counts appeared to be related to high indoor humidity. Only four children were sensitized to fungi, and these children were also sensitized to other allergens, such as animal dander and pollen, and suffered from asthma, allergic rhinoconjuncitivits (AR) and atopic dermatitis (AD). Three of these four children also had high counts of aerospores in their homes. However, no consistent association between mould growth and sensitization to moulds could be observed. The health implications of indoor fungal exposure may be multifactorial.     

Heat flux from flames to vertical surfaces

Dimensional analysis is used to examine heat transfer from flames to vertical surfaces. Configurations include a line fire against a wall, a square burner flame against a wall and in a corner, and window flames impinging on a wall. Dimensionless parameters that affect flame heat flux include/l _f ,y/D,l _f /D andkD where is vertical distance,y is horizontal distance,l _f is flame length,D is burner dimension, andk is the flame absorption coefficient. Only the effect of these variables is shown. No general correlation is developed, and more data are needed before these results can be applied with confidence.This paper is a contribution of the National Institute of Standards and Technology and is not subject to copyright.