Browsing by Author "Schmidt, Olaf"

As the most abundant animals on earth, nematodes are a dominant component of the soil community. They play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns.

A simple, rapid and cost-effective laboratory method was developed for labelling soil-feeding earthworms simultaneously with N-15 and C-13. The method circumvents the production of labelled plant material and can be adapted to devise pulse-labelling or long-term labelling protocols. Soil was amended with (NH4+)-N-15 and incubated for 7 days. Then, U-C-13-glucose was added and endogeic earthworms, Aporrectodea caliginosa (Oligochaeta: Lumbricidae), were provided individually with 4 g of this pre-incubated soil. The labelling period was 4 days. The labelling efficiency (percentage of tracer retained in earthworm tissues) was estimated to be 15.8% for N-15 and 10.3% for C-13. The loss of N-15 and C-13 label from tissue and mucus was traced for 21 days post-labelling. Label loss from mucus was best described by a two-term exponential function, whereas the label loss in body tissue followed a single-term exponential function. Half-life estimates for the N-15 and C-13 tracers in body tissue were 16 and 37 days, respectively. (c) 2004 Elsevier Ltd. All rights reserved.

OBJECTIVE: Several recent reports have demonstrated the expression of luteinizing hormone-releasing hormone receptors by human ovarian and endometrial cancers. Controversy persists on the relevance of this finding, in particular whether these receptors mediate direct anti proliferative effects of luteinizing hormone-releasing hormone analogues. We correlated the expression of luteinizing hormone-releasing hormone receptors by well-characterized ovarian and endometrial cancer cell lines with the ability of luteinizing hormone-releasing hormone analogues to reduce their proliferation and studied the autoregulation of luteinizing hormone-releasing hormone receptor expression by luteinizing hormone-releasing hormone agonist triptorelin and antagonist cetrorelix. The expression of luteinizing hormone-releasing hormone receptors was assessed in a series of specimens from primary ovarian and endometrial cancers. STUDY DESIGN: Luteinizing hormone-releasing hormone receptor expression was assessed by semiquantitative reverse transcriptase-polymerase chain reaction and radioligand binding assay. Antiproliferative effects were ascertained by proliferation assays in the absence or presence of luteinizing hormone-releasing hormone analogues. RESULTS: Ovarian (4/6 cell lines) and endometrial (516 cell lines) cancer cell lines expressed luteinizing hormone-releasing hormone receptors. The proliferation of these luteinizing hormone-releasing hormone receptor-positive cell lines was dose- and time-dependently reduced by agonistic and antagonistic luteinizing hormone-releasing hormone analogues. Luteinizing hormone-releasing hormone receptor density was reduced to 80% of controls (control, 100%; P < .001) by luteinizing hormone-releasing hormone analogues. Seventy percent of primary ovarian cancers and 83% of primary endometrial cancers expressed luteinizing hormone-releasing hormone receptors. CONCLUSION: These findings suggest that luteinizing hormone-releasing hormone receptors that are expressed by human ovarian and endometrial cancer cell lines mediate direct antiproliferative effects of luteinizing hormone-releasing hormone analogues. Because most respective primary cancers expressed luteinizing hormone-releasing hormone receptors, these receptors might be used for novel antiproliferative therapeutic approaches and should be further evaluated.

ABSTRACT Soil organisms drive major ecosystem functions by mineralising carbon and releasing nutrients during decomposition processes, which supports plant growth, aboveground biodiversity and, ultimately, human nutrition. Soil ecologists often operate with functional groups to infer the effects of individual taxa on ecosystem functions and services. Simultaneous assessment of the functional roles of multiple taxa is possible using food‐web reconstructions, but our knowledge of the feeding habits of many taxa is insufficient and often based on limited evidence. Over the last two decades, molecular, biochemical and isotopic tools have improved our understanding of the feeding habits of various soil organisms, yet this knowledge is still to be synthesised into a common functional framework. Here, we provide a comprehensive review of the feeding habits of consumers in soil, including protists, micro‐, meso‐ and macrofauna (invertebrates), and soil‐associated vertebrates. We have integrated existing functional group classifications with findings gained with novel methods and compiled an overarching classification across taxa focusing on key universal traits such as food resource preferences, body masses, microhabitat specialisation, protection and hunting mechanisms. Our summary highlights various strands of evidence that many functional groups commonly used in soil ecology and food‐web models are feeding on multiple types of food resources. In many cases, omnivory is observed down to the species level of taxonomic resolution, challenging realism of traditional soil food‐web models based on distinct resource‐based energy channels. Novel methods, such as stable isotope, fatty acid and DNA gut content analyses, have revealed previously hidden facets of trophic relationships of soil consumers, such as food assimilation, multichannel feeding across trophic levels, hidden trophic niche differentiation and the importance of alternative food/prey, as well as energy transfers across ecosystem compartments. Wider adoption of such tools and the development of open interoperable platforms that assemble morphological, ecological and trophic data as traits of soil taxa will enable the refinement and expansion of the multifunctional classification of consumers in soil. The compiled multifunctional classification of soil‐associated consumers will serve as a reference for ecologists working with biodiversity changes and biodiversity–ecosystem functioning relationships, making soil food‐web research more accessible and reproducible.

Abstract Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change.

We tested experimentally if photoautotrophic microorganisms are a carbon source for invertebrates in temperate soils. We exposed forest or arable soils to a (CO2)-C-13-enriched atmosphere and quantified C-13 assimilation by three common animal groups: earthworms (Oligochaeta), springtails (Hexapoda) and slugs (Gastropoda). Endogeic earthworms (Allolobophora chlorotica) and hemiedaphic springtails (Ceratophysella denticulata) were highly C-13 enriched when incubated under light, deriving up to 3.0 and 17.0%, respectively, of their body carbon from the microbial source in 7 days. Earthworms assimilated more C-13 in undisturbed soil than when the microbial material was mixed into the soil, presumably reflecting selective surface grazing. By contrast, neither adult nor newly hatched terrestrial slugs (Deroceras reticulatum) grazed on algal mats. Non-photosynthetic (CO2)-C-13 fixation in the darkwas negligible. We conclude from these preliminary laboratory experiments that, in addition to litter and root-derived carbon from vascular plants, photoautotrophic soil surface microorganisms (cyanobacteria, algae) may be an ecologically important carbon input route for temperate soil animals that are traditionally assigned to the decomposer channel in soil food web models and carbon cycling studies.

Net carbon isotope discrimination (C-13 Delta(n)) in leaves from Thuja plicata, Larix x eurolepis and Picea sitchensis was assessed with the aim of exploring the potential use of leaf carbon isotope signatures as a physiological marker for the selection of shade-tolerant tree species. Leaf C-13 Delta(n) varied from 14.2 parts per thousand to 26.7 parts per thousand depending on incident irradiance and species and was negatively correlated with annual biomass increment. Under shaded conditions, variations in C-13 Delta(n) values were consistent with differences in instantaneous nitrogen use efficiency and the ratio of sub-stomatal intemal to external CO, concentration (C-i:C-a). Although changes in C-13 Delta(n) were consistent variations in instantaneous photosynthetic discrimination (C-13 Delta(i)) across all irradiances, we suggest that species-specific variations in C-i:C-a and other isotopic fractionation processes may influence C-13 Delta(n). We demonstrate that C-13 Delta(n) can be used to rank species according to shade tolerance (T plicata > R sitchensis > L. eurolepis) under shaded conditions only. Therefore, the proposed use of C-13 Delta(n) to select shade tolerance should be approached with caution because the ranking of individual species may depend on the light environment to which the material is exposed and what photosynthetic and other metabolic characteristics influence C-13 Delta(n). (c) 2006 Elsevier B.V. All rights reserved.

Histologically confirmed local recurrence of the rare entity of a granular cell tumor of the vulva was diagnosed in a 55-year-old patient with no signs of distant metastasis. Intraoperatively (local excision of mons pubis and inguinal lymphnodes), widespread regional metastasis with retroperitoneal lymphnode metastases were found. Postoperative restaging detected pulmonary, hepatic and skeletal metastases and the patient died of her disseminated disease within 4 months. Early diagnosis of the malignant phenotype of granular cell tumor using expression of S-100-protein, MIB-1, vimentin and p53 is suggested. Once a malignant granular cell tumor is diagnosed histologically, thorough staging procedure should be performed to exclude disseminated disease. If this is the case, radical surgery should be tried due to the lack of efficiency of radiotherapy and of systemic treatments. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

The effects of slurry application method and weather conditions after application on ammonia volatilisation are well documented, however, the effect on slurry N recovery in herbage is less evident due to large variability of results. The objective of this field experiment was to determine the recovery of cattle slurry NH4-N in herbage and soil in the year of application as affected by application method (trailing shoe versus broadcast) and season of application (spring versus summer), using N-15 as a tracer. In 2007 and 2008, N-15 enriched slurry was applied on grassland plots. N recovery in herbage and soil during the year of application was determined. Both spring and trailing shoe application resulted in significantly higher herbage DM yields, N uptake and an increased recovery of (NH4)-N-15-N in herbage. Additionally, the recovery of slurry (NH4)-N-15-N in the soil at the end of the growing season was increased. Spring and trailing shoe application reduced the losses of slurry (NH4)-N-15-N by on average 14 and 18 percentage points, respectively, which corresponded closely to ammonia volatilisation as predicted by the ALFAM model. It was concluded that slurry N recovery in temperate pasture systems can be increased by adjusting the slurry application method or timing.

Soil nematode feeding groups are a long-established trophic categorisation largely based on morphology and are used in ecological indices to monitor and analyse the biological state of soils. Stable isotope ratio analysis (C-13/C-12 and N-15/N-14, expressed as delta C-13 and delta N-15) has provided verification of, and novel insights into, the feeding ecology of soil animals such as earthworms and mites. However, isotopic studies of soil nematodes have been limited to date as conventional stable isotope ratio analysis needs impractically large numbers of nematodes (up to 1,000) to achieve required minimum sample weights (typically > 100 mu g C and N). Here, micro-sample near-conventional elemental analysis-isotopic ratio mass spectrometry (mu EA-IRMS) of C and N using microgram samples (typically 20 mu g dry weight), was employed to compare the trophic position of selected soil nematode taxa from four feeding groups: predators (Anatonchus and Mononchus), bacterial feeders (Plectus and Rhabditis), omnivores (Aporcelaimidae and Qudsianematidae) and plant feeder (Rotylenchus). Free-living nematodes were collected from conventionally and organically managed arable soils. As few as 15 nematodes, for omnivores and predators, were sufficient to reach the 20 mu g dry weight target. There was no significant difference in delta N-15 (p = 0 : 290) or delta C-13 (p = 0 : 706) between conventional and organic agronomic treatments but, within treatments, there was a significant difference in N and C stable isotope ratios between the plant feeder, Rotylenchus (delta N-15= 1.08 to 3.22 mUr parts per thousand , delta C-13 = -29.58 to -27.87 mUr) and all other groups. There was an average difference of 9.62 mUr in delta N-15 between the plant feeder and the predator group (delta N-15 = 9.89 to 12.79 mUr, delta C-13 = -27.04 to -25.51 mUr). Isotopic niche widths were calculated as Bayesian derived standard ellipse areas and were smallest for the plant feeder (1.37 mUr(2)) and the predators (1.73 mUr(2)), but largest for omnivores (3.83 mUr(2)). These data may reflect more preferential feeding by the plant feeder and predators, as assumed by classical morphology-based feeding groups, and indicate that omnivory may be more widespread across detritivore groups i.e. bacterial feeders (3.81 mUr(2)). Trophic information for soil nematodes derived from stable isotope analysis, scaled as finely as species level in some cases, will complement existing indices for soil biological assessment and monitoring, and can potentially be used to identify new trophic interactions in soils. The isotopic technique used here, to compare nematode feeding group members largely confirm their trophic relations based on morphological studies.

Brown rot decay removes cellulose and hemicellulose from wood-residual lignin contributing up to 30% of forest soil carbon-and is derived from an ancestral white rot saprotrophy in which both lignin and cellulose are decomposed. Comparative and functional genomics of the "dry rot" fungus Serpula lacrymans, derived from forest ancestors, demonstrated that the evolution of both ectomycorrhizal biotrophy and brown rot saprotrophy were accompanied by reductions and losses in specific protein families, suggesting adaptation to an intercellular interaction with plant tissue. Transcriptome and proteome analysis also identified differences in wood decomposition in S. lacrymans relative to the brown rot Postia placenta. Furthermore, fungal nutritional mode diversification suggests that the boreal forest biome originated via genetic coevolution of above- and below-ground biota.