Short-Term Impact of Recycling-Derived Fertilizers on Their P Supply for Perennial Ryegrass ().

Various nutrient recycling technologies are currently under development in order to alleviate the dependency of non-renewable raw material for the production of mineral phosphorus fertilizers commonly used in agriculture. The resulting products, such as struvites and ashes, need to be assessed for their application as so-called recycling-derived fertilizers (RDFs) in the agricultural sector prior to commercialization. Here, we conducted a short-term (54 days) trial to investigate the impact of different phosphorus fertilizers on plant growth and the soil P cycling microbiota.

Arbuscular Mycorrhiza Support Plant Sulfur Supply through Organosulfur Mobilizing Bacteria in the Hypho- and Rhizosphere.

This study aimed to elucidate the role of bacteria colonising mycorrhizal hyphae in organically bound sulfur mobilisation, the dominant soil sulfur source that is not directly plant available. The effect of an intact mycorrhizal symbiosis with access to stable isotope organo-S enriched soils encased in 35 µm mesh cores was tested in microcosms with and . Hyphae and associated soil were sampled from static mesh cores with mycorrhizal ingrowth and rotating mesh cores that exclude mycorrhizal ingrowth as well as corresponding rhizosphere soil, while plant shoots were analysed for S uptake.

Cultivation Conditions of Spinach and Rocket Influence Epiphytic Growth of .

Leafy vegetables are associated with Listeriosis outbreaks due to contamination with Listeria monocytogenes. To date, contradictory findings were reported on spinach, rocket, and kale, where some studies reported growth of L. monocytogenes, while others did not.

International Spread of Multidrug-Resistant Rhodococcus equi.

A multidrug-resistant clone of the animal and human pathogen Rhodococcus equi, MDR-RE 2287, has been circulating among equine farms in the United States since the 2000s. We report the detection of MDR-RE 2287 outside the United States. Our finding highlights the risk for MDR-RE spreading internationally with horse movements.

Design and Construction of Repacked Soil Columns for Measuring Solute Transport, Plant Growth and Soil Biota.

Researchers face a number of challenges in the construction of soil columns which can affect the outcome of their experiments. The use of intact soil cores closely mimics actual field conditions. However, the excavation of large intact soil cores is a time-consuming, labor-intensive process and may lead to soil compaction that would influence the solute transport behavior of the soil column.

Growth Potential of on Refrigerated Spinach and Rocket Leaves in Modified Atmosphere Packaging.

Minimally processed ready-to-eat (RTE) vegetables are increasingly consumed for their health benefits. However, they also pose a risk of being ingested with food-borne pathogens. The present study investigated the ability of RTE spinach and rocket to support the growth of as previous studies provided contradicting evidence.

Sulfatase Assay to Determine Influence of Plants on Microbial Activity in Soil.

Sulfatase activity is often used as a measure of the activity of soil microorganisms. It is thus a suitable tool to investigate the response of microbes to plants. Here we present a method to determine the influence of various genotypes on the function of soil microbiota using the sulfatase as a quantitative measure.

Sulfate fertilization supports growth of ryegrass in soil columns but changes microbial community structures and reduces abundances of nematodes and arbuscular mycorrhiza.

The increased use of sulfate fertilizers to compensate for soil sulphur (S) limitation in agricultural soils may affect soil microbes and micro-fauna involved in S mobilization. Here, columns with podzolic soil material and ryegrass (Lolium perenne) were fertilized with 0, 5, 10 and 20 kg ha (S0/S5/S10/S20) inorganic sulfate-S alongside a full complement of other nutrients. In the S10 and S20 columns, significantly higher amounts of sulfate were present in soil solution.

One-time phosphate fertilizer application to grassland columns modifies the soil microbiota and limits its role in ecosystem services.

This study evaluated the effect of one-time phosphate fertilization on the soil microbiota, its cycling of phosphorus (P) and grass growth. Soil columns were established in a greenhouse using a P-limited Irish soil (index 1), planted with Lolium perenne and fertilized with 0 (control), 5 (quarter), 10 (half) and 20 (full)kgPha as inorganic phosphate. Only traces of phosphate in soil solution were detected over the 14week experiment, even after phosphate fertilization.

Inoculation density is affecting growth conditions of Listeria monocytogenes on fresh cut lettuce.

Listeria monocytogenes is a particular risk for the ready-to-eat food sector because of its ability to grow in various environmental conditions. In the literature, growth and survival of L. monocytogenes on food is tested using inoculation densities ranging from less than 10 to over 10 CFU g.

A 3-year multi-food study of the presence and persistence of Listeria monocytogenes in 54 small food businesses in Ireland.

The problem of assessing the occurrence of the food-borne pathogen Listeria monocytogenes in the food chain, and therefore the risk of exposure of the human population, is often challenging because of the limited scope of some studies. In this study the occurrence of L. monocytogenes in food from four major food groups, dairy products, meats, seafood and vegetables, and associated food processing environments in Ireland was studied over a three-year period.

Bacterial Mobilization of Nutrients From Biochar-Amended Soils.

Soil amendments with biochar to improve soil fertility and increase soil carbon stocks have received some high-level attention. Physical and chemical analyses of amended soils and biochars from various feedstocks are reported, alongside some evaluations of plant growth promotion capabilities. Fewer studies investigated the soil microbiota and their potential to increase cycling and mobilization of nutrients in biochar-amended soils.

Chemically and biologically-mediated fertilizing value of manure-derived biochar.

This study evaluates the potential of manure-derived biochars in promoting plant growth and enhancing soil chemical and biological properties during a 150day pot experiment. Biochars from pyrolysis of poultry litter (PL) and swine manure (SM) at 400 and 600°C, and a commonly available wood chip (WC) biochar produced at high temperature (1000°C) were incorporated to silt-loam (SL) and sandy (SY) soils on a 2% dry soil weight basis. Ryegrass was sown and moisture was adjusted to 60% water filled pore space (WFPS).

Oxalate secretion by ectomycorrhizal Paxillus involutus is mineral-specific and controls calcium weathering from minerals.

Trees and their associated rhizosphere organisms play a major role in mineral weathering driving calcium fluxes from the continents to the oceans that ultimately control long-term atmospheric CO2 and climate through the geochemical carbon cycle. Photosynthate allocation to tree roots and their mycorrhizal fungi is hypothesized to fuel the active secretion of protons and organic chelators that enhance calcium dissolution at fungal-mineral interfaces. This was tested using (14)CO2 supplied to shoots of Pinus sylvestris ectomycorrhizal with the widespread fungus Paxillus involutus in monoxenic microcosms, revealing preferential allocation by the fungus of plant photoassimilate to weather grains of limestone and silicates each with a combined calcium and magnesium content of over 10 wt.

The role of bacteria and mycorrhiza in plant sulfur supply.

Plant growth is highly dependent on bacteria, saprophytic, and mycorrhizal fungi which facilitate the cycling and mobilization of nutrients. Over 95% of the sulfur (S) in soil is present in an organic form. Sulfate-esters and sulfonates, the major forms of organo-S in soils, arise through deposition of biological material and are transformed through subsequent humification.

The role of sulfur- and phosphorus-mobilizing bacteria in biochar-induced growth promotion of Lolium perenne.

Plants rely on microorganisms to mobilize organically and inorganically bound sulfur (S) and phosphorus (P) in which the plant can then readily utilize. The aim of this study was to investigate the role of S- and P-mobilizing bacteria in plant growth promotion in biochar-amended soil, which has been rarely investigated so far. Pot experiments of Lolium perenne were established on S and P limited soil with 1% or 2% biochar (Miscanthus × giganteus) or without biochar (control) for a period of 126 days.

Profiling the diversity of microbial communities with single-strand conformation polymorphism (SSCP).

Genetic fingerprinting techniques for microbial community analysis have evolved over the last decade into standard applications for efficient and fast differentiation of microbial communities based on their diversity. These techniques commonly analyze the diversity of PCR products amplified from extracted environmental DNA usually utilizing primers hybridizing to suspected conserved regions of the targeted genes. In comparison to the more commonly applied terminal restriction fragment length polymorphism (TRFLP) or denaturing gradient gel electrophoresis (DGGE) techniques, the here-described single-strand conformation polymorphism (SSCP) fingerprinting technique features some advantageous key characteristics.

Degradation of benzo[a]pyrene by bacterial isolates from human skin.

Polycyclic aromatic hydrocarbons (PAHs) are some of the most widespread xenobiotic pollutants, with the potentially carcinogenic high-molecular-weight representatives being of particular interest. However, while in eukaryotes, the cytochrome P450 (CYP)-mediated activation of benzo[a]pyrene (B[a]P) has become a model for metabolism-mediated carcinogenesis, the oxidative degradation of B[a]P by microorganisms is less well studied. This should be reason for concern as the human organ most exposed to environmental PAHs is the skin, which at the same time is habitat to a most diverse population of microbial commensals.

Bacterial communities established in bauxite residues with different restoration histories.

Bauxite residue is the alkaline byproduct generated when alumina is extracted from bauxite ores and is commonly deposited in impoundments. These sites represent hostile environments with increased salinity and alkalinity and little prospect of revegetation when left untreated. This study reports the establishment of bacterial communities in bauxite residues with and without restoration amendments (compost and gypsum addition, revegetation) in samples taken in 2009 and 2011 from 0 to 10 cm depth.

Shifts in desulfonating bacterial communities along a soil chronosequence in the forefield of a receding glacier.

Forefields of receding glaciers are unique and sensitive environments representing natural soil chronosequences, where sulfate availability is assumed to be a limiting factor. Bacterial mineralization of organosulfur is an important sulfate-providing process in soils. We analyzed the diversity of sulfonate-desulfurizing (desulfonating) bacteria in the Damma glacier forefield on the basis of the key gene asfA by terminal restriction fragment length polymorphism and clone libraries.

Sulfonate desulfurization in Rhodococcus from wheat rhizosphere communities.

Organically bound sulfur makes up about 90% of the total sulfur in soils, with sulfonates often the dominant fraction. Actinobacteria affiliated to the genus Rhodococcus were able to desulfonate arylsulfonates in wheat rhizospheres from the Broadbalk long-term field wheat experiment, which includes plots treated with inorganic fertilizer with and without sulfate, with farmyard manure, and unfertilized plots. Direct isolation of desulfonating rhizobacteria yielded Rhodococcus strains which grew well with a range of sulfonates, and contained the asfAB genes, known to be involved in sulfonate desulfurization by bacteria.

The role of Variovorax and other Comamonadaceae in sulfur transformations by microbial wheat rhizosphere communities exposed to different sulfur fertilization regimes.

Sulfonates are a key component of the sulfur present in agricultural soils. Their mobilization as part of the soil sulfur cycle is mediated by rhizobacteria, and involves the oxidoreductase AsfA. In this study, the effect of fertilization regime on rhizosphere bacterial asfA distribution was examined at the Broadbalk long-term wheat experiment, Rothamsted, UK, which was established in 1843, and has included a sulfur-free treatment since 2001.

High unique diversity of sulfate-reducing prokaryotes characterized in a depth gradient in an acidic fen.

The dissimilatory reduction of sulfate contributes to the retention of sulfur in acidic mineratrophic peatlands. Novel sulfate-reducing prokaryotes (SRPs) colonize these low-sulfate fens. This study assessed the community structures of SRPs in a depth gradient (0-50 cm) in a fen, located in the Fichtelgebirge (Spruce Mountains), Germany.

Desulfurization of aromatic sulfonates by rhizosphere bacteria: high diversity of the asfA gene.

The plant growth-promoting effect of Pseudomonas putida S-313 is associated with its ability to desulfurize arylsulfonates. To understand this further, other plant-associated bacteria able to desulfurize a range of arylsulfonates were isolated from the rhizospheres of winter and spring barley. The isolates belonged to the beta-proteobacteria, including bacteria from the Variovorax paradoxus group and from the Acidovorax genus.