Invertebrate grazing determines enzyme production by basidiomycete fungi

Extracellular enzymes produced by heterotrophic microorganisms in the soil are responsible for the decomposition of organic compounds. Basidiomycete fungi are the primary decomposer agents in temperate wooded ecosystems and contribute extensively to extracellular enzyme activity and nutrient mineralisation within soils. Growth and development of basidiomycete mycelia is influenced by soil-dwelling invertebrate grazers with potential implications for fungal activity and ecosystem functioning. The impacts of four invertebrate taxa belonging to Isopoda, Myriapoda, Collembola and Nematoda on the production of eight hydrolytic enzymes by four saprotrophic basidiomycetes (Phanerochaete velutina, Resinicium bicolor and two strains of Hypholoma fasciculare) were compared in a factorial microcosm study. Grazing generally increased enzyme production but invertebrates had species-specific impacts on enzyme activity. The magnitude of grazing influenced enzyme activity; macrofauna (woodlice and millipedes) induced the greatest responses. Enzymatic responses varied markedly between fungi. Grazing enhanced enzyme activity in the exploitative mycelial networks of P. velutina and H. fasciculare, while the opposite effects were observed in the explorative R. bicolor networks. The impacts of soil fauna on nutrient mineralisation depend on fungal community composition. β-glucosidase, cellobiohydrolase, N-acetylglucosaminidase, acid phosphatase and phosphodiesterase activities were affected most frequently by grazing and invertebrate activity, and thus had direct consequences for carbon, nitrogen and phosphorous cycling. The results indicate that invertebrate diversity and community composition may influence the spatial distribution and activity of extracellular enzymes with direct implications for nutrient mineralisation and trunover in woodland soils.     

Microsatellite DNA Analysis of Wild Hops, Humulus lupulus L.

To study the relationships and genetic diversity among wild hops, Humulus lupulus, we analyzed 133 samples of wild hops collected from Europe, Asia and North America using polymorphism on 11 microsatellite loci. Although only three primers showed bands in Japanese hops, all other samples showed polymorphic bands at most loci. There were no duplicate genotypes among samples of European, Chinese and North American hops, and each individual hop could be distinguished completely. The phylogenetic tree constructed from DA distance with the UPGMA method showed a large cluster comprised of European hops, although Russian hops from the Caucasus and Altai regions were separate from the European cluster. Chinese and North American samples gave distinct clusters suggesting genetic differentiation. This study has indicated that hop microsatellite DNA is differentiated, and is dependent upon the origin in regions of Europe, Asia and North America.     

Analysis of soil fungal communities by amplicon pyrosequencing: current approaches to data analysis and the introduction of the pipeline SEED

Fungi are important in soils as both decomposers and plant symbionts, and an understanding of the composition of their complex communities is thus indispensable to answer a variety of ecological questions. 454 Pyrosequencing is currently the method of choice for the in-depth analysis of fungal communities. However, the interpretation of its results is complicated by differences in data analysis approaches that make inter-study comparisons difficult. The pyrosequencing studies published so far have also used variable molecular targets in fungal rDNA. Although the ITS region and, in particular, ITS1 appear to be the most frequent sequencing targets, the use of various primers with different coverages of fungal groups remains a serious problem. Sequence length limits also vary widely across studies, and in many studies, length differences may negatively affect sequence similarity clustering or identification. Unfortunately, many studies neglect the need to correct for method-dependent errors, such as pyrosequencing noise or chimeric sequences. Even when performed, error rates in sequences may be high, and consensus sequences created by sequence clustering therefore better represent operational taxonomic units. We recommend a data analysis workflow that includes sequence denoising, chimera removal, sequence trimming before clustering and random resampling before calculating diversity parameters. The newly developed free pipeline (SEED) introduced here can be used to perform all the required analytical steps. The improvement and unification of data analysis procedures should make future studies both more reliable and comparable and allow meta-studies to be performed to provide more general views on fungal diversity, biogeography or ecology.     

Kinematic Viscosity and Shear Stress of Used Engine Oil

The goal of this paper describes kinematic viscosity and shear stress of two used engine oils, which have been taken from two different passenger cars. Kinematic viscosity and shear stress are two of the most important physical behaviours of fluids, especially lubricating fluids. In this paper the authors have focused on engine oil. Knowledge of these properties of engine oil is very important due to its lifetime. The experiments have been done using digital rotary rheometer Anton Paar DV-3 P with use of TR8 spindle and special adapter for a small amount of sample （20 mL）. Two different engine oils have been observed--first from passenger car Renault Scenic with petrol engine （engine capacity 1.6 dm3） and the second from passenger car Skoda Roomster with diesel engine （engine capacity 1.4 dm3）. Castrol Magnatec 10W-40 engine oil has been taken from Renault car and Shell Helix Ultra Extra 5W-30 engine oil has been taken from ~koda car. Service interval of change oil has been set to 15,000 km and samples of used engine oils have been taken after 1,500 km. Only first samples of used engine oils have been taken after raid of 20 km. All samples of used engine oils have been compared with new （unused） engine oils same specification. The measured values of kinematic viscosity and shear stress have been modeled using linear function. The coefficients of correlation R have been achieved high values （0.88-0.96）. The obtained models can be used to prediction of engine oil flow behaviour.     

Low molecular weight poly(lactic acid) microparticles for controlled release of the herbicide metazachlor: preparation, morphology, and release kinetics

The preemergence chloroacetamide herbicide metazachlor was encapsulated in biodegradable low molecular weight poly(lactic acid) micro- and submicroparticles, and its release to the water environment was investigated. Three series of particles, S, M, and L, varying in their size (from 0.6 to 8 μm) and with various initial amounts of the active agent (5%, 10%, 20%, 30% w/w) were prepared by the oil-in-water solvent evaporation technique with gelatin as biodegradable surfactant. The encapsulation efficiencies reached were about 60% and appeared to be lower for smaller particles. Generally, it was found that the rate of herbicide release decreased with increasing size of particles. After 30 days the portions of the herbicide released for its highest loading (30% w/w) were 92%, 56%, and 34% for about 0.6, 0.8, and 8 μm particles, respectively. The release rates were also lower for lower herbicide loadings. Metazachlor release from larger particles tended to be a diffusion-controlled process, while for smaller particles the kinetics was strongly influenced by an initial burst release.     

Combined effects of salinity and phosphorus availability on growth,gas exchange,and nutrient status of Catapodium rigidum

The combined effects of NaCl-salinity and phosphorus deficiency on biomass production, nutritional status, and photosynthetic activity were studied in Catapodium rigidum: an annual Poacea with fodder potential. Plants were grown in hydroponic conditions for 55 days under two phosphorus (P) supply: 5 (low) or 180?µmol KH₂PO₄ (sufficient), in the absence or presence of 100?mM NaCl. Obtained results demonstrated that both salinity and P deficiency treatments applied separately reduced substantially plant growth and CO₂ assimilation rate with a more marked impact of salt stress. Salinity has no substantial effect on both shoot P concentrations and phosphorus acquisition efficiency independently of P availability. The highest decrease in plant growth (?91%) was observed in plants simultaneously submitted to both stresses suggesting an additive effect of the two stresses and that P deficiency increased the susceptibility of C. rigidum to salinity. This may be linked to a significant decrease in potassium acquisition (?95%), K/Na selectivity ratio (?73%), stomatal conductance (?66%), CO₂ assimilation rate (?64%), and shoot water content (66%). Furthermore, plants cultivated under combined salinity and sufficient P supply displayed higher stomatal conductance, CO₂ assimilation rate, K/Na selectivity ratio, and plant growth than plants cultivated under combined effects of salinity and P deficiency. These results suggest that adding P to saline soils could be an alternative for alleviating the negative effects of salinity and may ameliorate salinity tolerance.     

Eco-geographic distribution of <Emphasis Type="Italic">Cicer isauricum</Emphasis> P.H. Davis and threats to the species

Wild Cicer species are considered as useful genetic resources for resistance to biotic and abiotic stresses due to limited resistance in cultivated chickpeas. As a wild perennial species in the genus Cicer L., Cicer isauricum P.H. Davis is an endemic species to Turkey and endangered status according to the International Union for Conservation of Nature criteria. Here we report on its eco-geographic distribution and environmental stresses that affect the species, and advocate for its in situ and ex situ conservation. A new population of the species was discovered in Geyikbay?r?, Güllük Mountains in Antalya, Turkey. Cicer isauricum not only suffers from significant biotic stresses such as ascochyta blight [Ascochyta rabiei (Pass.) Labr.], pod borer (Helicoverpa armigera Hübner) and broomrape (Orobanche sp.), but is also subjected to drought and heat stress in its habitat. Infection with ascochyta blight in natural habitats was diagnosed by molecular techniques, and pod borer and broomrape were observed only phenotypically. PCR amplification of the internal transcribed spacer region of genomic DNA from cultured fungal isolates, yielded sequences with 100% nucleotide identity with the corresponding sequence in GeneBank for Didymella rabiei Kovachevski (anamorph: A. rabiei). The pathogen may have co-evolved with C. isauricum in the newly discovered site. Because C. isauricum is exposed to drought and accompanying heat stress in its natural habitat, it appears able to tolerate heat stress up to 45 °C during podding stage and terminal drought in late summer from its woody, deep rooting. C. isauricum bears multiple flowers per axil, a potentially useful trait in cultivated chickpea. In conclusion, C. isauricum is a potential genetic source for resistance to biotic and abiotic stresses, in need of greater protection due to its endangered status.     

Confirmation of <Emphasis Type="Italic">Peronospora agrimoniae</Emphasis> as a distinct species

Leaves with typical symptoms of downy mildew were found on common agrimony in the Czech Republic in 2014 and 2015 and at several locations in Germany from 2010 to 2014. The causal agent of downy mildew of agrimony was often reported as Peronospora agrimoniae, but sometimes also as P. sparsa. Morphological characteristics of the pathogens found in both countries are in the range of previous works for P. agrimoniae, but also other downy mildews parasitic on Rosaceae, rendering their discrimination based on published observations difficult. For molecular identification sequencing of several loci (nrITS rDNA, cox1 and cox2) was performed. Phylogenetic analyses based on nrITS rDNA clearly separated P. agrimoniae from other Peronospora species infecting Rosaceae. Thus, considering P. agrimoniae as separate species seems justified. Two German specimens were identical to two Czech samples in both nrITS rDNA and cox1 mtDNA sequences, but differed in a single nucleotide substitution in cox2 region. To our knowledge, this is the first verified record of P. agrimoniae on common agrimony in the Czech Republic.