Effects of increased temperature and aquatic fungal diversity on litter decomposition

Climate warming and biodiversity loss are two major factors threatening freshwaters. Aquatic hyphomycetes are fungi that play a key role in organic matter turnover in streams. To assess the impacts of temperature increase and aquatic hyphomycete diversity on plant-litter decomposition, we manipulated fungal assemblage composition at two levels of diversity (four and eight species) under ambient temperature of 16 °C and two regimes of temperature increase differing in 8 °C: abrupt versus gradual increase from 16 to 24 °C. The effects were evaluated on leaf-litter decomposition, fungal biomass and reproduction. Results showed faster leaf decomposition under increased temperature, but no differences were found between an abrupt and a gradual increase in temperature. Assemblage composition was the major factor controlling fungal biomass and reproduction, while fungal diversity was only critical to maintain reproduction.     

Survival and growth of microscopic fungi derived from tropical regions under future heat waves in the Pannonian Biogeographical Region

Warming and heat waves are predicted by different climate models in the near future in the Pannonian Biogeographical Region (PBR). These climatic effects may have impact on the prevalence and distribution of certain fungal species of this area. In this study the effects of predicted climate scenarios were tested on fungi being endemic or unintentionally introduced by global trade from regions of warm temperate climate. Common fungal species were selected for the study and exposed to heat waves during 7 days according to two climate scenarios: one moderately (RCP 4.5, T_avg = 27 °C, T_max = 35 °C, RH: 100%) and one strongly pessimistic (RCP 8.5, T_avg = 30 °C, T_max = 40 °C, RH: 100%) that include predictions for the Central Hungarian Region for July 2050. According to our results, Aspergillus flavus, Aspergillus niger, Aspergillus tubingensis and Fusarium strains introduced from tropical regions tolerated heat waves, unlike Penicillium and Talaromyces spp. and endemic Cladosporium spp. which were unable to grow under the RCP 8.5 treatment. The effects of climate change on fungi raise new issues not only from economic and health perspectives, but also in relation with plant protection and environment. Our results suggest that heat waves driven by climate change promote the colonization and growth of the tested strains of non-native fungi more likely than that of the native ones.     

A viscometric study of the biodegradation of photographic gelatin by fungi isolated from cinematographic films

The biodegradation of photographic gelatin grade (Bloom 225) material was studied by viscometry in aqueous solution (at 37 °C, 6.67% w/w) using filamentous fungi isolated and identified from cinematographic film stored in different Spanish archives. From viscosity data, different variables such as molecular weight and chain scission were calculated. To ensure initial spore suspension concentration was standardized for all the biodegradation experiments, a correlation between transmittance at 530 nm of fungal spore suspensions and the corresponding cytometric determination of populations was established for all the fungal strains studied in this work. The bioassay experiments were carried out at 25 and 4 °C using an initial concentration of fungi of 4.5×10⁵ conidia/mL except in the case of the genus Alternaria, where the concentration was 10 times lower. The fungal strains were three species of Aspergillus, i.e., A .ustus, A. nidulans var. nidulans, A. versicolor, seven Penicillium chrysogenum strains, and Cladosporium cladosporioides, Alternaria alternata, Mucor racemosus, Phoma glomerata, and Trichoderma longibrachiatum. All were gelatinase positive. Through the viscosity decay profiles with bioassay-time and the corresponding calculated chain scission, the relative quantitative gelatinase efficiency of these fungi has been evaluated.     

“Mini-community” simulation revealed the differences of endophytic fungal communities between the above- and below-ground tissues of Ephedra sinica Stapf

The microecology of endophytic fungi in special habitats, such as the interior of different tissues from a medicinal plant, and its effects on the formation of metabolites with different biological activities are of great importance. However, the factors affecting fungal community formation are unclear. This study is the first to utilize “mini-community” remodeling to understand the above phenomena. First, high-throughput sequencing technology was applied to explore the community composition and diversity of endophytic fungi in the above-ground tissues (Ea) and below-ground tissues (Eb) of Ephedra sinica. Second, fungi were obtained through culture-dependent technology and used for “mini-community” remodeling in vitro. Then, the effects of environmental factors, partner fungi, and plant tissue fluid (internal environment) on endophytic fungal community formation were discussed. Results showed that environmental factors played a decisive role in the selection of endophytic fungi, that is, in Ea and Eb, 93.8% and 25.3% of endophytic fungi were halophilic, respectively, and 10.6% and 60.2% fungi were sensitive to high temperature (33 °C), respectively. Meanwhile, pH had little effect on fungal communities. The internal environment of the plant host further promoted the formation of endophytic fungal communities.     

Metabolic network reconstruction,growth characterization and 13C-metabolic flux analysis of the extremophile Thermus thermophilus HB8

Thermus thermophilus is an extremely thermophilic bacterium with significant biotechnological potential. In this work, we have characterized aerobic growth characteristics of T. thermophilus HB8 at temperatures between 50 and 85 °C, constructed a metabolic network model of its central carbon metabolism and validated the model using ¹³C-metabolic flux analysis (¹³C–MFA). First, cells were grown in batch cultures in custom constructed mini-bioreactors at different temperatures to determine optimal growth conditions. The optimal temperature for T. thermophilus grown on defined medium with glucose was 81 °C. The maximum growth rate was 0.25 h⁻¹. Between 50 and 81 °C the growth rate increased by 7-fold and the temperature dependence was described well by an Arrhenius model with an activation energy of 47 kJ/mol. Next, we performed a ¹³C-labeling experiment with [1,2-¹³C] glucose as the tracer and calculated intracellular metabolic fluxes using ¹³C–MFA. The results provided support for the constructed network model and highlighted several interesting characteristics of T. thermophilus metabolism. We found that T. thermophilus largely uses glycolysis and TCA cycle to produce biosynthetic precursors, ATP and reducing equivalents needed for cells growth. Consistent with its proposed metabolic network model, we did not detect any oxidative pentose phosphate pathway flux or Entner-Doudoroff pathway activity. The biomass precursors erythrose-4-phosphate and ribose-5-phosphate were produced via the non-oxidative pentose phosphate pathway, and largely via transketolase, with little contribution from transaldolase. The high biomass yield on glucose that was measured experimentally was also confirmed independently by ¹³C–MFA. The results presented here provide a solid foundation for future studies of T. thermophilus and its metabolic engineering applications.     

If you can’t stand the heat,stay out of the city: Thermal reaction norms of chitinolytic fungi in an urban heat island

Elevated soil and air temperatures in urban heat islands have been exerting evolutionary pressure on organisms for decades in some cities. We measured thermal reaction norms (18–26 °C) for growth rate of four species of common chitinolytic fungi from an oak forest in an urban heat island and a corresponding rural area. Urban isolates of Chrysosporium pannorum and Trichoderma koningii grew faster than rural isolates at 26 °C, but grew slower than rural isolates at 18 °C. Urban isolates of Torulomyces lagena and Penicillium bilaii grew as fast or faster than rural isolates at all temperatures. These differences in thermal reaction norms between urban and rural isolates suggest that urbanization has caused both thermal specialization and counter-gradient variation in the fungal community.     

Does maritime Antarctic permafrost harbor environmental fungi with pathogenic potential?

We assessed the potentially pathogenic fungi present in Antarctic permafrost and the overlying active layer on King George, Robert, Livingston and Deception Islands in the South Shetland Islands archipelago, maritime Antarctica. Permafrost and active layer sub-samples were incubated at 37 °C to select fungi able to grow inside the human body. A total of 67 fungal isolates were obtained, 27 from the permafrost and 40 from the active layer. These represented 18 taxa of the genera Alternaria, Aspergillus, Curvularia, Penicillium, Rhodotorula and Talaromyces. The majority of fungi detected occurred exclusively either in the permafrost or the active layer at each site. Only Aspergillus thermomutatus, Penicillium cf. chrysogenum and Rhodotorula cf. mucilaginosa were present in both permafrost and active layer samples from the same site. The yeast R. cf. mucilaginosa was recovered from both in at least two sites. The genus Penicillium was the most abundant and widely distributed genus in both permafrost and active layer samples across the sites sampled. All fungal isolates were screened using enzymatic, pH and antifungal assays to identify their virulence potential. Aspergillus hiratsukae, A. thermomutatus and R. cf. mucilaginosa, known human opportunistic fungi, were identified, displayed phospholipase, esterase, proteinase and hemolytic activities. All three also displayed the ability to grow at 40°, 45° and/or 50 °C and resistance to fluconazole and itraconazole; additionally, R. cf. mucilaginosa showed resistance to amphotericin B and viability after 100 d at ?80 °C. A. thermomutatus UFMGCB 17415 killed the entire larvae of Tenebrio molitor in six days and R. cf. mucilaginosa UFMGCB 17448 and 17473 in three and four days, respectively. The melting of maritime Antarctic permafrost as a result of climate change may threaten the release of wild strains of pathogenic fungi geographically isolated for long time, which may in turn be transported within and beyond Antarctica by different biological and non-biological vectors.     

Adaptation of soil microbial growth to temperature: Using a tropical elevation gradient to predict future changes

Terrestrial biogeochemical feedbacks to the climate are strongly modulated by the temperature response of soil microorganisms. Tropical forests, in particular, exert a major influence on global climate because they are the most productive terrestrial ecosystem. We used an elevation gradient across tropical forest in the Andes (a gradient of 20°C mean annual temperature, MAT), to test whether soil bacterial and fungal community growth responses are adapted to long‐term temperature differences. We evaluated the temperature dependency of soil bacterial and fungal growth using the leucine‐ and acetate‐incorporation methods, respectively, and determined indices for the temperature response of growth: Q₁₀ (temperature sensitivity over a given 10oC range) and T_min (the minimum temperature for growth). For both bacterial and fungal communities, increased MAT (decreased elevation) resulted in increases in Q₁₀ and T_min of growth. Across a MAT range from 6°C to 26°C, the Q₁₀ and T_min varied for bacterial growth (Q_10–20 = 2.4 to 3.5; T_min = ?8°C to ?1.5°C) and fungal growth (Q_10–20 = 2.6 to 3.6; T_min = ?6°C to ?1°C). Thus, bacteria and fungi did not differ significantly in their growth temperature responses with changes in MAT. Our findings indicate that across natural temperature gradients, each increase in MAT by 1°C results in increases in T_min of microbial growth by approximately 0.3°C and Q_10–20 by 0.05, consistent with long‐term temperature adaptation of soil microbial communities. A 2°C warming would increase microbial activity across a MAT gradient of 6°C to 26°C by 28% to 15%, respectively, and temperature adaptation of microbial communities would further increase activity by 1.2% to 0.3%. The impact of warming on microbial activity, and the related impact on soil carbon cycling, is thus greater in regions with lower MAT. These results can be used to predict future changes in the temperature response of microbial activity over different levels of warming and over large temperature ranges, extending to tropical regions.     

Effect of available P and phenolics on mineral N release in acidified spruce forest: connection with lignin-degrading enzymes and bacterial and fungal communities

We conducted over four months a short-term laboratory incubation experiment to find the best prediction parameters (i.e. initial chemical characteristics) to explain differences in microbial respiration rates and mineral N (DIN) release in different litter in an acidified spruce forest. In addition, we wanted to find the link between the activity of key extracellular ligninolytic enzymes, phenoloxidases (PhOx) and peroxidases (Perox), microbial respiration and composition of fungal and bacterial communities. Samples of spruce needles (Picea abies) and litter of four dominant understorey vegetation; lady fern (Athyrium alpestre), blueberry (Vaccinium myrtillus), reedgrass (Calamagrostis villosa) and hair grass (Avenella flexuosa), were collected in 2005, 2006 and 2007 from six sites located in watersheds of two glacial lakes (Plesne Lake and Certovo Lake) in the Bohemian Forest, Czech Republic. Litter samples were incubated at 0 and 10 °C in laboratory controlled conditions for 90 days. Activities of PhOx and PerOx, and C mineralization rate were measured regularly each 14 days. Litter quality characteristics and endophytic microbial community structure, based on 16SrDNA-DGGE fingerprint of bacteria and ITS-DGGE of fungi, were determined at the beginning and end of litter incubation. Our results showed a close correlation of phenolics/P_OX with DIN release (r > 0.74, p < 0.001). Using multivariate analyses, P_OX seems to play an important role in the change of litter fungal and bacterial community composition. At 0 °C the fungal and bacterial communities of reedgrass and blueberry litter changed in relation to P_OX and Perox activity, while at 10 °C the fungal communities after the incubation were additionally affected by the phenolics/N_TOT and phenolics/P_TOT ratios.     

Role of calcium in alleviating effect of salinity on germination of Phragmites karka seeds

Phragmites karka (Retz.) Trin, ex. steud, a perennial reed with creeping rhizome from the family Poaceae, is distributed as pure population in brackish water swamps. Populations primarily propagate using ramets but also produce numerous seeds which form part of the seed bank after dispersal and are exposed to extremes of temperature, drought, and salinity stress. Seeds were germinated under a range of salinity (0, 100, 200, 300, 400, 500 mM NaCl) and temperature (10/20 °C, 15/25 °C, 20/30 °C, 25/35 °C, night/day) regimes in 12 h light:12 h dark photoperiod or in complete darkness with 0, 5, 10, 25 mM CaCl₂. Salinity, absence of light and high temperature (25/35 °C) reduced germination while calcium generally reversed this effect, more so at cooler temperature regimes. Calcareous soil around Karachi would help alleviate the salinity effect on the germination of P. karka and facilitate its survival.     

Studies toward the comprehension of fungal-macroalgae interaction in cold marine regions from a biotechnological perspective

In marine ecosystems, macroalgae are the habitat for several microorganisms, fungi being among them. In the Antarctic benthic coastal ecosystem, macroalgae play a key role in organic matter cycling. In this study, 13 different macroalgae from Potter Cove and surrounding areas were sampled and 48 fungal isolates were obtained from six species, four Rhodophyta Ballia callitricha, Gigartina skottsbergii, Neuroglossum delesseriae and Palmaria decipiens, and two Phaeophyceae: Adenocystis utricularis and Ascoseira mirabilis. Fungal isolates mostly belonged to the Ascomycota phylum (Antarctomyces, Cadophora, Cladosporium, Penicillium, Phialocephala, and Pseudogymnoascus) and only one to the phylum Mucoromycota. Two of the isolates could not be identified to genus level, implying that Antarctica is a source of probable novel fungal taxa with enormous bioprospecting and biotechnological potential. 73% of the fungal isolates were moderate eurypsychrophilic (they grew at 5–25 °C), 12.5% were eurypsychrophilic and grew in the whole range, 12.5% of the isolates were narrow eurypsychrophilic (growth at 15–25 °C), and Mucoromycota AUe4 was classified as stenopsychrophilic as it grew at 5–15 °C. Organic extracts of seven macroalgae from which no fungal growth was obtained (three red algae Georgiella confluens, Gymnogongrus turquetii, Plocamium cartlagineum, and four brown algae Desmarestia anceps, D. Antarctica, Desmarestia menziesii, Himantothallus grandifolius) were tested against representative fungi of the genera isolated in this work. All extracts presented fungal inhibition, those from Plocamium cartilagineum and G. turquetii showed the best results, and for most of these macroalgae, this represents the first report of antifungal activity and constitute a promising source of compounds for future evaluation.     

Temperature alters interspecific relationships among aquatic fungi

Temperature is a key factor in determining the structure and performance of fungal assemblages on decomposing plant litter in streams. However, little is known of how temperature affects interspecific relationships among fungi. We compared the growth of four aquatic hyphomycetes co-occurring in temperate streams, in monocultures and all species combinations when exposed to five temperatures from 11 to 27 °C. In monocultures, maximum growth rates of Heliscus submersus, Lunulospora curvula and Varicosporium elodeae occurred at 27 °C whereas Articulospora tetracladia had the lowest growth rate. At 27 °C, the increase in species diversity had no effect on the growth of V. elodeae, increased the growth of H. submersus and L. curvula, and decreased the growth of A. tetracladia. Results suggest that within a species' optimal temperature range the growth of that species increases with higher fungal diversity, while outside this range growth decreases with diversity.     

Reproduction and population parameters of the Nearctic predator Geocoris punctipes at constant and varying temperature regimes

The heteropteran predator Geocoris punctipes (Say) has been used in augmentative biological control since 2000 to control Lepidoptera. However, surprisingly, few data are available about the influence of temperature on its population development, which is of key importance to plan the number and moment of releases to obtain sufficient pest reduction. The objective of this study was to evaluate daily and total fecundity, longevity and life table parameters (m_x, l_x, r_m, R, λ, T and TD) of G. punctipes at constant (16.8°C, 21.5°C, 24.5°C and 28.3°C) and corresponding varying (day/night) (21/11°C, 24/18°C, 27/21°C and 30/26°C) temperatures. Pairs of adult predators aged 24 h and originating from nymphs exposed to the same temperature regimes were kept at the above‐mentioned temperature regimes in Petri dishes containing Anagasta kuehniella (Zeller) eggs and an oviposition substrate. Tests were conducted in climatic chambers at the different temperature regimes and a RH 70 ± 10% and a 14L: 10D photoperiod. Reproduction, longevity and life table parameters were significantly affected by temperature, with clear differences between treatments at low (16.8°C, 21/11°C, 21.5°C, 24/18°C) or a high (24.5°C, 27/21°C, 28.3°C, 30/26°C) temperature regimes. Highest reproduction and fastest population growth of G. punctipes took place at average temperatures ranging from 24.5°C to 30°C, and neither reproduction nor population growth was negatively influenced by varying temperatures at any of the temperature regimes.     

Phanerochaete chrysosporium inoculation shapes the indigenous fungal communities during agricultural waste composting

Inoculation with exogenous white-rot fungi has been proven to be an efficient method to promote lignocellulose biodegradation during agricultural waste composting. Indigenous fungal communities, the most important organisms responsible for mineralization and decomposition of lignocellulosic materials in composts, can be affected by sample properties and other biotic factors. This research was conducted to determine the effects of the Phanerochaete chrysosporium inoculation on the indigenous fungal communities during agricultural waste composting. Fungal communities in samples with different inoculation regimes were investigated by sequencing and quantitative PCR. Results showed that P. chrysosporium inoculants produced significant negative effects on the indigenous fungal community abundance during the thermophilic stage. Samples inoculated during Phase II contained higher proportion of Acremonium chrysogenum and Galactomyces geotrichum, while those non-inoculated samples were dominated by Coprinopsis cinerea and Scytalidium thermophilum. Moreover, the indigenous fungal community abundance was significantly correlated with the C/N ratio, water soluble carbon and moisture content (P < 0.05). Redundancy analysis indicated that the most variation in distribution of indigenous fungal community structure was statistically explained by nitrate, C/N ratio, and moisture content, factors which solely explained 29.6 % (F = 30.316, P = 0.002), 25.6 % (F = 26.191, P = 0.002) and 10.0 % (F = 10.249, P = 0.002) of the variation in the indigenous fungal community structure, respectively.     

Do spawn storage conditions influence the colonization capacity of a wheat-straw-based substrate by Agaricus subrufescens?

Storage conditions of the spawn of edible fungi are of major importance to facilitate the production of mushrooms. Here, standard storage conditions at 10 °C or 15 °C were used and the potential of colonization of standard European compost by the tropical species Agaricus subrufescens was assessed during the spawn running phase. Two lignocellulolytic activities, laccase and CMC-cellulase, were enhanced after storage compared to control as well as substrate transformation, as described by the aromaticity ratio and a humification ratio calculated from NMR data. This result indicates that mycelium growth probably occurred during storage at 10 or 15 °C, leading to a larger amount of biomass in the inoculum. Moreover, the microbial functional diversity of the substrate was favored, showing that the electivity of the substrate was maintained. Thus, these findings indicate that recommendations for the mushroom producers can be established for A. subrufescens cultivation under European standard conditions.     

Temperature sensitivity of biomass‐specific microbial exo‐enzyme activities and CO2 efflux is resistant to change across short‐ and long‐term timescales

Accurate representation of temperature sensitivity (Q₁₀) of soil microbial activity across time is critical for projecting soil CO₂ efflux. As microorganisms mediate soil carbon (C) loss via exo‐enzyme activity and respiration, we explore temperature sensitivities of microbial exo‐enzyme activity and respiratory CO₂ loss across time and assess mechanisms associated with these potential changes in microbial temperature responses. We collected soils along a latitudinal boreal forest transect with different temperature regimes (long‐term timescale) and exposed these soils to laboratory temperature manipulations at 5, 15, and 25°C for 84 days (short‐term timescale). We quantified temperature sensitivity of microbial activity per g soil and per g microbial biomass at days 9, 34, 55, and 84, and determined bacterial and fungal community structure before the incubation and at days 9 and 84. All biomass‐specific rates exhibited temperature sensitivities resistant to change across short‐ and long‐term timescales (mean Q₁₀ = 2.77 ± 0.25, 2.63 ± 0.26, 1.78 ± 0.26, 2.27 ± 0.25, 3.28 ± 0.44, 2.89 ± 0.55 for β‐glucosidase, N‐acetyl‐β‐d ‐glucosaminidase, leucine amino peptidase, acid phosphatase, cellobiohydrolase, and CO₂ efflux, respectively). In contrast, temperature sensitivity of soil mass‐specific rates exhibited either resilience (the Q₁₀ value changed and returned to the original value over time) or resistance to change. Regardless of the microbial flux responses, bacterial and fungal community structure was susceptible to change with temperature, significantly differing with short‐ and long‐term exposure to different temperature regimes. Our results highlight that temperature responses of microbial resource allocation to exo‐enzyme production and associated respiratory CO₂ loss per unit biomass can remain invariant across time, and thus, that vulnerability of soil organic C stocks to rising temperatures may persist in the long term. Furthermore, resistant temperature sensitivities of biomass‐specific rates in spite of different community structures imply decoupling of community constituents and the temperature responses of soil microbial activities.     

Molecular characterization of airborne fungi in caves of the Mogao Grottoes, Dunhuang, China

In this study, we analyzed air samples collected from several sites within the Mogao Grottoes, Dunhuang, China. The samples were collected each month from September 2008 to August 2009 from an open cave (OC), a semi-open cave (SC), a closed cave (CC), and the entrance (EN) of the Mogao Grottoes. Sampling was carried out using a six-stage Andersen FA-I sampler; then samples were cultured and fungal isolates were identified by partial sequencing of their internal transcribed spacer (ITS) region. Eleven different fungal genera were found, and the most prevalent was Cladosporium, followed by Fusarium, Penicillium, Alternaria, and Aspergillus. The fungal community composition varied among the four sites. Fungal community structure was significantly related to site (r = −0.293, p = 0.039) and to time of year (r = −0.523, p = 0.000). The concentrations and abundance of airborne fungi varied greatly throughout the year at the four sampling sites. Meteorological parameters (e.g., temperature, relative humidity) and the number of visitors also influenced both abundance and community structure of airborne fungi in the Mogao Grottoes.     

Codon-optimized expression and characterization of a pH stable fungal xylanase in Pichia pastoris

Novel xylanase (EC 3.2.1.8) is in great demand due to its industrial significance. In this study, we have developed and characterized a novel xylanase-producing yeast strain. This mature xylanase gene xyn11A consists of 870 base pairs and belongs to GH11 family. The gene sequence was optimized and synthesized, and was then cloned into yeast vector pGAPZαA under the control of the constitutive GAP promoter. SDS-PAGE analysis indicates that Xyn11A is extracellularly expressed as a glycosylated protein in P. pastoris. Xyn11A is optimally active at 70 °C and pH 7.4. This xylanase retained more than 90% of its activity after incubation at 50 °C and 60 °C for up to 1 h. Xyn11A is also stable over a wide range of pH (2.0–11.0). Most metal ions tested such as copper (Cu²⁺) and lead (Pb²⁺) have little inhibitory effects on Xyn11A. It is also resistant to pepsin and proteinase K digestion, retaining 80% and 90% of its activity after digestion at 37 °C for 1 h, respectively. Those superior properties make Xyn11A a robust xylanase with great potential for industrial use. To the best of our knowledge, this is the first report of xylanase from the fungus Corynascus thermophilus.     

Temperature-dependent functional response of Diglyphus isaea and Hemiptarsenus zilahisebessi parasitizing Liriomyza sativae

This study was conducted to address the effect of different constant temperatures (15, 20, 25, 30 and 35 °C) on the functional response of the parasitoid wasps Diglyphus isaea Walker and Hemiptarsenus zilahisebessi Erdös to different densities of Liriomyza sativae Blanchard (2, 4, 8, 16, 32 and 64 larvae) under laboratory conditions. The results revealed the Type II functional response for both parasitoids at different temperatures. The highest searching efficiency for D. isaea and H. zilahisebessi occurred at 25 °C (0.926 ± 0.211 h⁻¹) and 30 °C (1.012 ± 0.241 h⁻¹), respectively. In addition, the shortest handling time for D. isaea and H. zilahisebessi were observed at 25 °C (0.063 ± 0.008 h) and 30 °C (0.058 ± 0.008 h), respectively. These results demonstrated that H. zilahisebessi is more efficient at higher temperatures than D. isaea. Both parasitoids had higher parasitism performance when temperature increased (4.67 parasitized hosts/day at 15 °C vs 15.87 parasitized hosts/day at 25 °C for D. isaea and 3.89 parasitized hosts/day at 15 °C vs 17.24 parasitized hosts/day at 30 °C for H. zilahisebessi). In addition, a quadratic regression was found between handling time and temperature as well as between number of the parasitized larvae and temperature in D. isaea and H. zilahisebessi at different densities of L. sativae. This study provided a preliminary information on the parasitic behavior of these parasitoids and that D. isaea and H. zilahisebessi can be used properly beside other non-chemical approaches to manage L. sativae damage at a temperature range of 25–30 °C, respectively.     

Investigation of keratinolytic and non-keratinolytic fungi grown above or below a 1-cm sewage sludge blanket

This study investigated the incidence of keratinolytic and non-keratinolytic fungi grown above or below a 1-cm sewage sludge blanket. The hair baiting method was used. Incubation was carried out at 23 and 37  °C. The number of keratinolytic fungi occurrences below a sludge blanket (anoxic conditions) was almost two times smaller than the number of fungal occurrences above this blanket (oxic conditions). The anoxic conditions did not significantly affect the number of non-keratinolytic fungi. Qualitative differences were also observed. Trichophyton ajelloi with its teleomorph Arthroderma uncinatum and some other fungi were found to prefer oxic conditions. In the case of non-keratinolytic fungi, the most evident differences were observed at 37  °C. Aspergillus fumigatus prevailed above a sludge blanket, while Pseudallescheria boydii was the predominating species below this blanket. The incidence of keratinolytic fungi was dependent on sludge physico-chemical characteristics: mainly on sludge organic matter stabilization (total nitrogen and ammonium nitrogen contents, proteolytic activity and C:N ratio) and hygienization (total and fecal coliforms) factors.