New Deoxyribozymes for the Native Ligation of RNA.

Deoxyribozymes (DNAzymes) are small, synthetic, single-stranded DNAs capable of catalyzing chemical reactions, including RNA ligation. Herein, we report a novel class of RNA ligase deoxyribozymes that utilize 5'-adenylated RNA (5'-AppRNA) as the donor substrate, mimicking the activated intermediates of protein-catalyzed RNA ligation. Four new DNAzymes were identified by in vitro selection from an N random DNA library and were shown to catalyze the intermolecular linear RNA-RNA ligation via the formation of a native 3'-5'-phosphodiester linkage.

Sensitivity of the Population in Algeria to Quinone outside Inhibitors, Succinate Dehydrogenase Inhibitors and Demethylation Inhibitors.

Net blotch of barley caused by (Died.) Drechsler, is one of the most destructive diseases on barley in Algeria. It occurs in two forms: f.

Interpretation of sexual secondary characteristics (SSCs) in regulatory testing for endocrine activity in fish.

Secondary sexual characteristics (SSCs) are important features that have evolved in many fish species because of inter-individual competition for mates. SSCs are crucial not only for sexual selection, but also for other components of the reproductive process and parental care. Externally, they are especially clear in males (for instance, tubercles, fatpad, anal finnage, colouration) but are also externally present in the females (for instance, ovipositor).

Does hepatotoxicity interfere with endocrine activity in zebrafish (Danio rerio)?

Vitellogenin (VTG), a well-established biomarker for the diagnosis of endocrine activity in fish, is used in multiple OECD test guidelines (TG) to identify activities of chemicals on hormonal pathways. However, the synthesis of VTG may not only be modified by typical endocrine-related pathways, but also through non-endocrine-mediated processes. In particular, hepatotoxicity, i.

The Arabidopsis non-host defence-associated coumarin scopoletin protects soybean from Asian soybean rust.

The fungus Phakopsora pachyrhizi (Pp) causes Asian soybean rust (SBR) disease which provokes tremendous losses in global soybean production. Pp is mainly controlled with synthetic fungicides to which the fungus swiftly develops fungicide resistance. To substitute or complement synthetic fungicides in Asian soybean rust control, we aimed to identify antifungal metabolites in Arabidopsis which is not a host for Pp.

Free energy calculations elucidate substrate binding, gating mechanism, and tolerance-promoting mutations in herbicide target 4-hydroxyphenylpyruvate dioxygenase.

4-Hydroxyphenylpyruvate dioxygenase (HPPD) catalyzes the second reaction in the tyrosine catabolism and is linked to the production of cofactors plastoquinone and tocopherol in plants. This important biological role has put HPPD in the focus of current herbicide design efforts including the development of herbicide-tolerant mutants. However, the molecular mechanisms of substrate binding and herbicide tolerance have yet to be elucidated.

Risk assessment considerations for plant protection products and terrestrial life-stages of amphibians.

Some amphibians occur in agricultural landscapes during certain periods of their life cycle and consequently might be exposed to plant protection products (PPPs). While the sensitivity of aquatic life-stages is considered to be covered by the standard assessment for aquatic organisms (especially fish), the situation is less clear for terrestrial amphibian life-stages. In this paper, considerations are presented on how a risk assessment for PPPs and terrestrial life-stages of amphibians could be conducted.

Prospective aquatic risk assessment for chemical mixtures in agricultural landscapes.

Environmental risk assessment of chemical mixtures is challenging because of the multitude of possible combinations that may occur. Aquatic risk from chemical mixtures in an agricultural landscape was evaluated prospectively in 2 exposure scenario case studies: at field scale for a program of 13 plant-protection products applied annually for 20 yr and at a watershed scale for a mixed land-use scenario over 30 yr with 12 plant-protection products and 2 veterinary pharmaceuticals used for beef cattle. Risk quotients were calculated from regulatory exposure models with typical real-world use patterns and regulatory acceptable concentrations for individual chemicals.

Pathogenomic Analysis of Wheat Yellow Rust Lineages Detects Seasonal Variation and Host Specificity.

Recent disease outbreaks caused by (re-)emerging plant pathogens have been associated with expansions in pathogen geographic distribution and increased virulence. For example, in the past two decades' wheat yellow (stripe) rust, Puccinia striiformis f. sp.

A new urease-inhibiting formulation decreases ammonia volatilization and improves maize nitrogen utilization in North China Plain.

Overuse of urea, low nitrogen (N) utilization, and large N losses are common in maize production in North China Plain (NCP). To solve these problems, we conducted two field experiments at Shangzhuang and Quzhou in NCP to test the ability of a newly developed urease inhibitor product Limus to decrease NH volatilization from urea applied to maize. Grain yield, apparent N recovery efficiency (RE) and N balance when using urea applied with or without Limus were also measured over two maize growing seasons.

Optimizing the design of a reproduction toxicity test with the pond snail Lymnaea stagnalis.

This paper presents the results from two ring-tests addressing the feasibility, robustness and reproducibility of a reproduction toxicity test with the freshwater gastropod Lymnaea stagnalis (RENILYS strain). Sixteen laboratories (from inexperienced to expert laboratories in mollusc testing) from nine countries participated in these ring-tests. Survival and reproduction were evaluated in L.

Appropriate exposure estimates for wildlife risk assessments of crop protection products based on continuous radio telemetry: A case study with woodpigeons.

The registration of pesticides follows guidance published by the European Food Safety Authority (EFSA). As a default, the EFSA guidance document on risk assessment for birds and mammals assumes that animals feed exclusively on pesticide-treated fields. However, the guidance document suggests refining the risk via the proportion of food animals obtain from a treated field or specific crop (expressed via the portion of diet obtained from a treated area [PT value]).

Competitive Fitness of Phakopsora pachyrhizi Isolates with Mutations in the CYP51 and CYTB Genes.

Soybean rust (Phakopsora pachyrhizi) in Brazil is mainly controlled with applications of fungicides, including demethylation inhibitors (DMI) and quinone outside inhibitors (QoI). Isolates with less sensitivity to DMI and QoI have been reported, and these have been found to have mutations in the CYP51 and CYTB genes, respectively. There have been no reports of fitness costs in isolates with mutations in CYP51 and CYTB, and the aim of this work was to compare the competitive ability of isolates with lower DMI or QoI sensitivities with that of sensitive (wild-type) isolates.

Proposal for a unified nomenclature for target-site mutations associated with resistance to fungicides.

Evolved resistance to fungicides is a major problem limiting our ability to control agricultural, medical and veterinary pathogens and is frequently associated with substitutions in the amino acid sequence of the target protein. The convention for describing amino acid substitutions is to cite the wild-type amino acid, the codon number and the new amino acid, using the one-letter amino acid code. It has frequently been observed that orthologous amino acid mutations have been selected in different species by fungicides from the same mode of action class, but the amino acids have different numbers.

Emergence of succinate dehydrogenase inhibitor resistance of Pyrenophora teres in Europe.

Background: Net blotch caused by Pyrenophora teres is an important disease of barley worldwide. In addition to strobilurins (quinone ouside inhibitors) and azoles (demethylation inhibitors), succinate dehydrogenase inhibitors (SDHIs) are very effective fungicides for net blotch control. Recently, SDHI-resistant isolates have been found in the field.

Differences in the efficacy of carboxylic acid amide fungicides against less sensitive strains of Plasmopara viticola.

Background: Plasmopara viticola is controlled by fungicides with different modes of action, including carboxylic acid amides (CAAs). The aim of this study was to evaluate differences in the response of CAA-resistant P. viticola strains towards CAAs.

Population-level effects and recovery of aquatic invertebrates after multiple applications of an insecticide.

Standard risk assessment of plant protection products (PPP) combines "worst-case" exposure scenarios with effect thresholds using assessment (safety) factors to account for uncertainties. If needed, risks can be addressed applying more realistic conditions at higher tiers, which refine exposure and/or effect assessments using additional data. However, it is not possible to investigate the wide range of potential scenarios experimentally.

Interspecies gene transfer provides soybean resistance to a fungal pathogen.

Fungal pathogens pose a major challenge to global crop production. Crop varieties that resist disease present the best defence and offer an alternative to chemical fungicides. Exploiting durable nonhost resistance (NHR) for crop protection often requires identification and transfer of NHR-linked genes to the target crop.

Life-history trade-offs mediate 'personality' variation in two colour morphs of the pea aphid, Acyrthosiphon pisum.

Life-history trade-offs are considered a major driving force in the emergence of consistent behavioural differences (personality variation); but empirical tests are scarce. We investigated links between a personality trait (escape response), life-history and state variables (growth rate, size and age at first reproduction, age-dependent reproductive rates, lifetime reproductive success, life span) in red and green colour morphs of clonal pea aphids, Acyrthosiphon pisum. Escape response (dropping/non-dropping off a plant upon a predatory attack) was measured repeatedly to classify individuals as consistent droppers, consistent nondroppers or inconsistents.

On the mode of action of the herbicides cinmethylin and 5-benzyloxymethyl-1, 2-isoxazolines: putative inhibitors of plant tyrosine aminotransferase.

Background: The mode of action of the grass herbicides cinmethylin and 5-benzyloxymethyl-1,2-isoxazolines substituted with methylthiophene (methiozolin) or pyridine (ISO1, ISO2) was investigated.

Results: Physiological profiling using a series of biotests and metabolic profiling in treated duckweed (Lemna paucicostata L.) suggested a common mode of action for the herbicides.

Physionomics and metabolomics-two key approaches in herbicidal mode of action discovery.

Background: For novel herbicides identified in greenhouse screens, efficient research is important to discover and chemically optimise new leads with new modes of action (MoAs).

Results: The metabolic and physiological response pattern to a herbicide can be viewed as the result of changes elicited in the molecular and biochemical process chain. These response patterns are diagnostic of a herbicide's MoA.

Auxin herbicides: current status of mechanism and mode of action.

Synthetic compounds that act like phytohormonal 'superauxins' have been among the most successful herbicides used in agriculture for more than 60 years. These so-called auxin herbicides are more stable in planta than the main natural auxin, indole-3-acetic acid (IAA), and show systemic mobility and selective action, preferentially against dicot weeds in cereal crops. They belong to different chemical classes, which include phenoxycarboxylic acids, benzoic acids, pyridinecarboxylic acids, aromatic carboxymethyl derivatives and quinolinecarboxylic acids.

The herbicide flamprop-M-methyl has a new antimicrotubule mechanism of action.

Background: The herbicidal mode of action of flamprop-M-methyl [methyl N-benzoyl-N-(3-chloro-4-fluorophenyl)-D-alaninate] was investigated.

Results: For initial characterization, a series of bioassays was used, which indicated a mode of action similar to that of mitotic disrupter herbicides. Cytochemical fluorescence studies, which included monoclonal antibodies against polymerized tubulin, were applied to elucidate effects on mitosis and microtubule assembly in maize roots.