Diana Hofmann

• Forschungszentrum Jülich

Glyphosate is a broad-spectrum herbicide widely used. After years of extensive usage, many weed species have developed resistance due to both target-site (TSR) and non-target-site resistance mechanisms (NTSRs). Alopecurus myosuroides is a competitive weed species. Greenhouse monitoring trials in Germany have revealed reduced glyphosate efficacy aga...

Mined rock phosphate is expected to become a scarce resource within the next few decades as global phosphorus (P) deposits are declining. As a result, mineral P fertilizer will be less available and more expensive. Therefore, improved knowledge is needed on other P resources, for example, apatite fertilizers derived from the by‐products of iron min...

The current study is aimed at investigating the level of polycyclic aromatic hydrocarbons (PAHs) and bis(2-ethylhexyl) phthalate (BEHP), which pose a potential risk to human health, in soil samples collected from a teff-Acacia decurrerns-charcoal production system (TACP system) in northern Ethiopia. Soil samples were collected from the TACP system...

Toxic breakdown products of young Camelina sativa (L.) Crantz, glucosinolates can eliminate microorganisms in the soil. Since microorganisms are essential for phosphate cycling, only insensitive microorganisms with phosphate-solubilizing activity can improve C. sativa’s phosphate supply. In this study, ³³P-labeled phosphate, inductively coupled pla...

With the increased global interest in sequestering carbon in soil, it is necessary to understand the composition of different pools of soil organic matter (SOM) that cycle over suitably short timeframes. To explore in detail the chemical composition of agroecologically relevant yet distinct fractions of SOM, the light fraction of SOM (LFOM), the 53...

BACKGROUND and AIMS Glucosinolates and isothiocyanates of young Camelina sativa (L.) Crantz can eliminate microbial species in the soil. It was aimed to demonstrate that only isothiocyanate insensitive microorganisms with phosphate solubilizing activity can be successfully used to improve the plant´s phosphate supply. METHODS We performed rhizotron...

Many natural and anthropogenic soils are phosphorus (P) limited often due to larger P stocks sequestered in forms of low bioavailability. One of the strategies to overcome this shortage lies in the symbiosis of plants with mycorrhizal fungi, increasing the plant P uptake of these hardly accessible sources. However, little is known about mycorrhizal...

For the characterization of BOA-OH insensitive plants, we studied the time-dependent effects of the benzoxazolinone-4/5/6/7-OH isomers on maize roots. Exposure of Zea mays seedlings to 0.5 mM BOA-OH elicits root zone-specific reactions by the formation of dark rings and spots in the zone of lateral roots, high catalase activity on root hairs, and n...

Exposure of Zea mays seedlings to 0.5µM benzoxazolinone-4/5/6/7-OH allelochemicals elicits root zone specific reactions by formation of dark rings and spots in the zone of lateral roots,high catalase activity at root hairsand no visible defense reaction at the root tip. We studied short term effects on membrane lipids and fatty acids in maize root...

For the characterization of BOA-OH insensitive plants, we studied time-dependent effects of the benzoxazolinone-4/5/6/7-OH isomers on maize roots. Exposure of Zea mays seedlings to 0.5 mM BOA-OH elicits root zone specific reactions by formation of dark rings and spots in the zone of lateral roots, high catalase activity on root hairs and no visible...

Recent findings on soil organic matter (SOM) revealed that soil microorganisms are not only crucial for SOM formation through plant litter degradation but soil microbial biomass (SMB) may also directly contribute to SOM and its composition. However, the role and interactions of litter quality, microbial turnover and composition of SMB and SOM remai...

Information on the bioavailability and -accessibility of subsoil phosphorus (P) and how soil moisture affects its utilization by plants is scarce. The current study examined whether and to which degree wheat acquires P from subsoil allocated hydroxyapatite and how this could be affected by soil moisture. We investigated the 33P uptake by growing wh...

Purpose Pesticide contamination of river waters is a global problem, and therefore, authorities regularly monitor the water quality status. Especially, flood events might transport large pesticide loads downstream and impact adjacent areas such as sensible floodplain environments by deposing particle bound pesticides or by contaminating the environ...

The broad-scale herbicide glyphosate is used worldwide in crop management system to control weeds, facilitate harvests, prepare seed beds, and desiccate cover crops. Greenhouse monitoring trials on herbicide resistance occurrence and potential spread conducted regularly in Lower Saxony, Germany, revealed a reduced glyphosate efficacy against some p...

The United Nations Educational, Scientific and Cultural Organization (UNESCO) world natural heritage Tian Shan Mountains, situated in Central Asia, have experienced a dramatic increase in polycyclic aromatic hydrocarbon (PAH) contamination, not only because of increasing volumes of tourism-derived traffic but also because of the atmospheric transpo...

Algae effectively accumulate phosphorus (P) from the environment, qualifying them as a promising novel P fertilizer. We hypothesized that P in algae can be rapidly transformed in soil and mobilized for plant growth. To determine the fate of algal fertilizer in soil and to trace its efficiency for plant uptake, we labeled the algae Chlorella vulgari...

In this chapter we describe a method for quantification of 20 proteinogenic amino acids by liquid chromatography-mass spectrometry which affords neither derivatization nor the use of organic solvents. Analysis of the underivatized amino acids is performed by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) in th...

Dissolved organic matter (DOM) is part of the biogeochemical cycles of carbon and nutrients, carries pollutants and drives soil formation. The DOM concentration and properties along the water flow path through forest ecosystems depend on its sampling location and transformation processes. To improve our understanding of the effects of forest manage...

Phosphorus (P) research still lacks techniques for rapid imaging of P use and allocation in different soil, sediment, and biological systems in a quantitative manner. In this study, we describe a time-saving and cost-efficient digital autoradiographic method for in situ quantitative imaging of ³³P radioisotopes in plant materials. Our method combin...

Dissolved organic matter (DOM) is part of the biogeochemical cycles of carbon and nutrients, carries pollutants and drives soil formation. The DOM concentration and properties along the water flow path through forest ecosystems depend on its origin and transformation processes. To improve our understanding of the effects of forest management, espec...

AimsThe accumulation of organic layers in forests is linked to decreasing nutrient availability. Organic layers might represent a source of phosphorus (P) nutrition of trees in forests. Our aims were i) to test if the fate of P in a tree sapling-soil system differs between nutrient-poor and nutrient-rich sites, and ii) to assess the influence of or...

Algae are capable of accumulating nutrients from aqueous waste, which makes them a potential fertilizer. The ability of the fast growing Chlorella vulgaris strain IPPAS C1 to accumulate phosphorus (P) was probed in V-shaped plastic foil photobioreactors. The P uptake was 0.13–0.53 g(P)·m⁻²·day⁻¹ when the algal culture densities were kept between 0....

6-Methoxy-benzoxazolin-2(3H)-one (MBOA) is a degradation product derived from 2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), one of the bioactive compounds found e.g., in maize. Here we present hitherto unknown 6-methoxy-4-nitro-benzoxazolin-2(3H)-one (NMBOA) produced in Czapek medium by Pantoea ananatis (Enterobacteriaceae). P. anan...

The objective of this work was to investigate the chemical composition and the quantitative changes in soil organic matter (SOM) fractions in response to multiple historical inputs of charcoal that ceased >60 years ago. The topsoil (0–5 cm) and subsoil (5–20 cm) samples of charcoal enriched soils and the unamended reference soils were assessed for...

Apatite is the principal primary phosphorus (P) source in the environment; yet there is no consensus on how it can be synthesized for controlled microcosm studies, particularly not in labelled form. Here, we present a methodology that allows for the production of stoichiometric 33Phosphorus (33P)-labelled hydroxyapatite powders produced by a simple...

Core Ideas Cation exchange (CE) on illite, a main sorption process for Cs ⁺ , is driven by Cs ⁺ concentration. Undefined CE and surface complexation on OM are main sorption processes for Sr ²⁺ . ¹³⁷ Cs ⁺ migrated only into shallow depths of a few centimeters after 3 yr. ⁹⁰ Sr ²⁺ migrated into deeper layers of the soil due to competitive sorption....

We present the results of a two years study on the contamination of the Luxembourg Sandstone aquifer by metolachlor-ESA and metolachlor-OXA, two major transformation products of s-metolachlor. The aim of the study was twofold: (i) assess whether elevated concentrations of both transformation products (up to 1000 ng/l) were due to fast flow breaktho...

Rhamnolipids are biosurfactants consisting of rhamnose (Rha) molecules linked through a β-glycosidic bond to 3-hydroxyfatty acids with various chain lengths, and they have an enormous potential for various industrial applications. The best known native rhamnolipid producer is the human pathogen Pseudomonas aeruginosa, which produces short-chain rha...

Water-extractable organic matter (WEOM) is the most dynamic and bioavailable fraction of the soil organic matter pool. Although the litter floor is considered the main source of WEOM, roots also release a great amount of labile organic compounds through rhizodeposition processes. This makes the rhizosphere, the small soil volume in proximity to the...

A facultative, microbial micro-community colonizing roots of Abutilon theophrasti Medik. supports the plant in detoxifying hydroxylated benzoxazolinones. The root micro-community is composed of several fungi and bacteria with Actinomucor elegans as a dominant species. The yeast Papiliotrema baii and the bacterium Pantoea ananatis are actively invol...

Background and aimsMacropores may be preferential root pathways into the subsoil. We hypothesised that the presence of macropores promotes P-uptake from subsoil, particularly at limited water supply in surface soil. We tested this hypothesis in a rhizotron experiment with spring wheat (Triticum aestivum cv. Scirocco) under variation of fertilisatio...

The human pathogenic bacterium Pseudomonas aeruginosa produces rhamnolipids, glycolipids with functions for bacterial motility, biofilm formation, and uptake of hydrophobic substrates. Rhamnolipids represent a chemically heterogeneous group of secondary metabolites composed of one or two rhamnose molecules linked to one or mostly two 3-hydroxyfatty...

Pantoea ananatis is a bacterium associated with other microorganisms on Abutilon theophrasti Medik. roots. It converts 6-hydroxybenzoxazolin-2(3H)-one (BOA-6-OH), a hydroxylated derivative of the allelochemical benzoxazolin-2(3H)-one, into 6-hydroxy-5-nitrobenzo[d]oxazol-2(3H)-one. The compound was identified by NMR and mass spectrometric methods....

The soil-plant transfer of Cs-137 and Sr-90 in different crops was determined with respect to the present-day amendment practice of using digestate from biogas fermenters. The studies were performed using large lysimeters filled with undisturbed luvisol monoliths. In contrast to the conservative tracer, Br(-), neither of the studied radionuclides s...

In the Lower Rhine Embayment (western Germany), the Neogene lignite bearing sequence is rich in large fossil wood trunks. Woods collected from sand-filled channels of a meandering river system (Pliocene: Reuver series) and from coal seams (Miocene: seams Garzweiler, Frimmersdorf and Morken) were investigated by Curie-point pyrolysis coupled with ga...

It is important to take measurements shortly after a forest trees clearcut in order to understand its environmental effects and to determine the possible counter measures to limit the impact. Soil samples were therefore collected from a forest site before and after the clearcut, i.e. 2013 and 2014, respectively, in order to understand the changes i...

Biopurification systems, such as biofilters, are biotechnological tools to prevent point sources of pesticide pollution stemming from on-farm operations. For the purification processes pesticide sorption and mineralization and/or dissipation are essential and both largely depend on the type of filling materials and the pesticide in use. In this pap...

The major detoxification product in maize roots after 24 h benzoxazolin-2(3H)-one (BOA) exposure was identified as glucoside carbamate resulting from rearrangement of BOA-N-glucoside, but the pathway of N-glucosylation, enzymes involved and the site of synthesis were previously unknown. Assaying whole cell proteins revealed the necessity of H2O2 an...

Allelopathic benzoxazolin-2(3H)-one (BOA) from rye mulches inhibits Portulaca oleracea and Amaranthus retroflexus but not Abutilon theophrasti (Schulz et al. 2013). Although Abutilon theophrasti has developed multifaceted strategies in coping with BOA, which includes support of the root colonizing fungus Actinomucor elegans, more reactive derivativ...

An unusual ice type, called hair ice, grows on the surface of dead wood of broad-leaf trees at temperatures slightly below 0 °C. We describe this phenomenon and present physical, chemical, and biological investigations to gain insight in the properties and processes related to hair ice. Tests revealed that the biological activity of a winter-active...

An unusual ice type, called hair ice, grows on the surface of dead wood of broad-leaf trees at temperatures slightly below 0 °C. We describe this phenomenon and present physical, chemical, and biological investigations to gain insight in the properties and processes related to hair ice. Tests revealed that the biological activity of a winter-active...

Recently we showed that during the degradation of sulfadiazine (SDZ) by Microbacterium lacus strain SDZm4 the principal metabolite 2-aminopyrimidine (2-AP) accumulated to the same molar amount in the culture as SDZ disappeared (Tappe et al. Appl Environ Microbiol 79:2572-2577, 2013). Although 2-AP is considered a recalcitrant agent, long-term lysim...

Abutilon theophrasti Medik., previously found to be rather insensitive to benzoxazinoid containing rye mulch and the allelochemical benzoxazolin-2(3H)-one (BOA), can be associated with the zygomycete Actinomucor elegans, whereby the fungus colonizes the root relatively superficially and mainly in the maturation zone. The fungus mitigates necrosis o...

Depending on the dosage, volatile compounds of aromatic plants can have beneficial or harmful effects on neighbored plants. Low concentrations of some monoterpenes can promote plant growth whereas higher ones inhibit the growth, affects the cytoskeleton, alter gene expressions, lead to permanent stomata opening and desiccation of receiver plants. I...

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) groundwater monitoring in the Zwischenscholle aquifer in western Germany revealed concentrations exceeding the threshold value of 0.1 μg L−1 and increasing concentration trends even 20 yr after its ban. Accordingly, the hypothesis was raised that a continued release of bound atrazine...

Veterinary antibiotics administered to livestock can be unintentionally released into the environment, for example by the application of manure to soils. The fate of such antibiotics in soils is mostly determined by sorption and degradation processes, including transformation. There is a need to further examine the combined transformation and sorpt...

Chlordecone is a persistent organochlorine insecticide that, even decades after its ban, poses a threat to the environment and human health. Nevertheless, its environmental fate in soils has scarcely been investigated, and elementary data on its degradation and behaviour in soil are lacking. The mineralisation and sorption of chlordecone and the fo...

Hair-ice is a rather unknown phenomenon. In contrast to generally known frost needles, originating from atmospheric water and expanding e.g. from plant surfaces in all directions, hair ice grows from the basis of wet, rotten hardwood. The hair-like, flexible, linear structures may reach up to 10 cm in length without any ramifications. Hair-ice appe...

Sulfadiazine (SDZ)-degrading bacterial cultures were enriched from the topsoil layer of lysimeters that were formerly treated with manure from pigs medicated with 14C-labeled SDZ. The loss of about 35% of the applied radioactivity after an incubation period of 3 years was attributed to CO2 release due to mineralization processes in the lysimeters....

The application of rare earth complexes in several techniques and technologies requires their strong, i.e. preferably covalent, fixation to a substrate. The particularly useful luminescence properties of – readily available – rare earth β-diketonate complexes can widely be maintained on co-ligation with an epoxi-functionalised 1,10-phenanthroline....

Soil drying and rewetting may alter the release and availability of aged pesticide residues in soils. A laboratory experiment was conducted to evaluate the influence of soil drying and wetting on the release of pesticide residues. Soil containing environmentally long-term aged (9-17 years) (14) C-labeled residues of the herbicides ethidimuron (ETD)...

Risk assessment of xenobiotics requires a comprehensive understanding of their transformation in the environment. As most of the transformation processes usually involve a redox reaction or a hydrolysis as the first steps of the transformation, we applied an approach that uses an electrochemical cell to investigate model "redox" reactions in aqueou...

The fate of the 14C-labeled herbicides ethidimuron (ETD), methabenzthiazuron (MBT), and the fungicide anilazine (ANI) in soils was evaluated after long-term aging (9-17 years) in field based lysimeters subject to crop rotation. Analysis of residual 14C activity in the soils revealed 19% (ETD soil; 0-10 cm depth), 35% (MBT soil; 0-30), and 43% (ANI...

A laboratory experiment was conducted to evaluate the effect of alternating soil drying and wetting on the release of aged 14C-labeled pesticide residues and their distribution in soil organic fractions (humic acids, fulvic acids, and humin substances). The used soils (gleyic cambisol; Corg 1.2%, pH 7.2) were obtained from the upper soil layer of t...

Soil drying and rewetting usually increases the release of xenobiotics like pesticides present in agricultural soils. Besides the effect on the release of two aged 14C-labeled pesticide residues we focus on the characterisation of simultaneously remobilized dissolved organic carbon (DOC) to gain new insights into structure and stability aspects of...

Sixteen priority polycyclic aromatic hydrocarbons (PAHs) in surface water samples were analyzed by gas chromatograph-mass spectrometer (GC-MS) to study their distribution and characterizing sources. The water samples were collected from five sites (J1-J5) in the Jialing River of Chongqing downtown area from September 2009 to August 2010. The result...

In this chapter, we describe a method for quantification of 20 proteinogenic amino acids as well as 13 (15)N-labeled amino acids by liquid chromatography-mass spectrometry without the need for derivatization and use of organic solvents. Analysis of the underivatized amino acids is performed by liquid chromatography-electrospray ionization-tandem ma...

Using small-angle neutron scattering, the unperturbed chain dimensions of a series of poly(alkylene oxide)s (PAO’s) were studied as a function of side-chain length. The PAO’s were obtained using anionic ring-opening polymerization methods. The deuterated monomers were synthesized from commercially available precomponents. A systematic decrease of t...

Electrochemistry (EC) coupled to mass spectrometry (MS) has already been successfully applied to metabolism research for pharmaceutical applications, especially for the oxidation behaviour of drug substances. Xenobiotics (chemicals in the environment) also undergo various conversions; some of which are oxidative reactions. Therefore, EC-MS might be...

The continuous enzymatic gas/solid bio-reactor serves both for the production of volatile fine chemicals and flavors on an industrial scale and for thermodynamically controlled investigation of substrate and water effects on enzyme preparations for research purposes. Here, we comparatively investigated the molecular effects on the operational stabi...

Redox cofactors like NADH and NADPH are essential for the catalytic activity of several oxidoreductases. Here, we describe a comparative study of the thermal degradation products of both cofactors in the dry and liquid states. The degradation products were first separated, detected, and quantified by high-performance liquid chromatography (HPLC). S...

To assess the potential occurrence of accelerated herbicide degradation in soils, the mineralization and persistence of (14)C-labeled and nonlabeled atrazine was evaluated over 3 months in two soils from Belgium (BS, atrazine-treated 1973-2008; BC, nontreated) and two soils from Germany (CK, atrazine-treated 1986-1989; CM, nontreated). Prior to the...

Carotenoid turnover was investigated in mature leaves of Arabidopsis (Arabidopsis thaliana) by 14CO2 pulse-chase labeling under control-light (CL; 130 micromol photons m(-2) s(-1)) and high-light (HL; 1,000 micromol photons m(-2) s(-1)) conditions. Following a 30-min 14CO2 administration, photosynthetically fixed 14C was quickly incorporated in bet...

Twenty-two years after the last application of ring-14C-labeled atrazine at customary rate (1.7 kg ha(-1)) on an agriculturally used outdoor lysimeter, atrazine is still detectable by means of accelerated solvent extraction and LC-MS/MS analysis. Extractions of the 0-10 cm soil layer yielded 60% of the residual 14C-activity. The extracts contained...

In order to sustain the structural integrity of the containment and other safety relevant components i.e. to avoid a detonation of the hydrogen-air mixture generated during a severe accident in light water reactors, passive auto-catalytic recombiners (PAR) are used for hydrogen removal in many European nuclear power plants (NPP). In 1999, the Germa...

The long-term behavior of the herbicide atrazine and its metabolites in the environment is of continued interest in terms of risk assessment and soil quality monitoring. Aqueous desorption, detection, and quantification of atrazine and its metabolites from an agriculturally used soil were performed 22 years after the last atrazine application. A ly...

A method has been developed for quantification of 20 amino acids as well as 13 15N-labeled amino acids in barley plants. The amino acids were extracted from plant tissues using aqueous HCl–ethanol and directly analyzed without further purification. Analysis of the underivatized amino acids was performed by liquid chromatography (LC)–electrospray io...

An all-glass miniaturized light-phase rotary perforator for the enrichment of polar compounds has been modified/miniaturized and applied. Its application is demonstrated here for the analysis of nitrophenols and dinitrophenols from low-concentration/low-volume samples. For the method development of high-performance liquid chromatography-mass spectr...

At the Emsland nuclear power station, a total of 58 autocatalytic hydrogen recombiners were backfitted in 1999 as an additional measure of risk reduction in connection with major hydrogen releases after events going beyond the design basis. Annual in-service inspections after 2002 revealed that some of the catalyst sheets developed startup delays a...

Benzoxazinoids were identified in the early 1960s as secondary metabolites of the grasses that function as natural pesticides and exhibit allelopathic properties. Benzoxazinoids are synthesized in seedlings and stored as glucosides (glcs); the main aglucone moieties are 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA) and 2,4-dihydroxy-7-methoxy-2...

Within the framework of a precautionary investigation performed in cooperation between the German Nuclear Power Plant Emsland (KKE), Forschungszentrum Juelich (FZJ) and the RWTH Aachen University deactivation effects on catalyst sheets of passive autocatalytic recombiners (PAR) were studied. The composition of the fouling and possible age-induced d...

Doratomyces stemonitis (Hyphomycetales, Dematiaceae) is a saprotrophic fungus belonging to the mycobiota of the cereal rhizosphere. The fungus is able to metabolize benzoxazolin-2-(3H)-one and a variety of its derivatives including higher plant detoxification products, microbial degradation products and the chemically rather stable 2-amino-(3H)-phe...

New ways of the covalent immobilization of Mn(III) and Mo(IV) Salen complexes on a mesoporous silica support to produce a stable heterogeneous catalyst for epoxidation reactions are reported. Peptide and ester interactions were employed to anchor the metal Salen complex on the organo-modified silica framework. Electrospray MS, FTIR, TGA, ICP-OES an...

Incubation of Zea mays cv. Nicco seedlings with 6-methoxybenzoxazolin-2(3H)-one (MBOA) led to a minor detoxification product hitherto only found in Poaceae. This new compound was identified as 1-(2-hydroxy-4-methoxyphenylamino)-1-deoxy-beta-glucoside 1,2-carbamate (1) (methoxy glucoside carbamate) and represents an analogue to the previously descri...

An extensive set of gaseous and particulate organic compounds was quantified before an orographic cloud passage at the upwind site of the research region in Thüringer Wald. Samples were collected with two different time resolutions, 2 h for gaseous species and spray absorber samples and the whole cloud event duration to determine the concentrations...

An overview of the two FEBUKO aerosol–cloud interaction field experiments in the Thüringer Wald (Germany) in October 2001 and 2002 and the corresponding modelling project MODMEP is given. Experimentally, a variety of measurement methods were deployed to probe the gas phase, particles and cloud droplets at three sites upwind, downwind and within an...

An extensive speciation of organic compounds was conducted during the FEBUKO cloud experiments in autumn 2001 and 2002. Three measurement sites were chosen at the Schmücke mountain in the Thüringer Wald region, Germany, which allowed to characterise air masses chemically before, during, and after their passage of a hill cap cloud. Concentrations of...

In order to identify natural nitrogen isotope variations of biologically important amino acids four derivatization reactions (t-butylmethylsilylation, esterification with subsequent trifluoroacetylation, acetylation and pivaloylation) were tested with standard mixtures of 17 proteinogenic amino acids and plant (moss) samples using GC-C-IRMS. The po...

An off-line method for rapid analysis of submicrometer organic atmospheric aerosol particles was developed. The method first uses condensational growth of submicrometer particles and then impaction to collect the particles for off-line chemical analysis. This condensation-growth and impaction system (C-GIS) converts the aerosol into a hydrosol that...

Atmospheric oxidation of biogenic hydrocarbons such as monoterpenes is believed to be a globally significant source of aerosols. Secondary and primary biogenic hydrocarbons were determined in airborne particles. The particles were collected on quartz fibre filters in summer 2001 in a Norway spruce forest (Fichtelgebirge, Germany) at two different h...