Farmers’ management of functional biodiversity goes beyond pest management in organic European apple orchards

Supporting functional biodiversity (FB), which provides natural pest regulation, is an environmentally sound and promising approach to reduce pesticide use in perennial cultures such as apple, especially in organic farming. However, little is known about farmers’ practices and motivations to implement techniques that favor FB, especially whether or not they really expect anything from FB in terms of pest regulation. In fact, FB-supporting techniques (FB-techniques) are massively questioned by practitioners due to inadequate information about their effectiveness. An interview survey was performed in eight European countries(i) to describe farmers’ practices and identify promising FB-techniques: (ii) to better understand their perceptions of and values associated with FB; and (iii) to identify potential drivers of (non-)adoption. Fifty-five advisors and 125 orchard managers with various degrees of experience and convictions about FB were interviewed and a total of 24 different FB-techniques which can be assigned to three different categories (ecological infrastructures, farming practices and redesign techniques) were described. Some were well-established measures (e.g., hedges and bird houses), while others were more marginal and more recent (e.g., animal introduction and compost). On average, farmers combined more than four techniques that had been implemented over a period of 13 years, especially during their establishment or conversion period. In general, it was difficult for farmers to evaluate the effectiveness of individual FB-techniques on pest regulation. They considered FB-techniques as a whole, targeting multiple species, and valued multiple ecosystem services in addition to pest regulation. The techniques implemented and their associated values differed among farmers who adopted various approaches towards FB. Three different approaches were defined: passive, active and integrated. Their appraisal of FB is even more complex because it may change with time and experience. These findings provide empirical evidence that the practical implementation of promising techniques remains a challenge, considering the diversity of situations and evaluation criteria. Increased cooperation between researchers, farmers and advisors should more effectively target research, advisory support and communication to meet farmers’ needs and perceptions

Removal of Uracil by Uracil DNA Glycosylase Limits Pemetrexed Cytotoxicity: Overriding the Limit with Methoxyamine to Inhibit Base Excision Repair

Uracil DNA glycosylase (UDG) specifically removes uracil bases from DNA, and its repair activity determines the sensitivity of the cell to anticancer agents that are capable of introducing uracil into DNA. In the present study, the participation of UDG in the response to pemetrexed-induced incorporation of uracil into DNA was studied using isogenic human tumor cell lines with or without UDG (UDG+/+/UDG−/−). UDG−/− cells were very sensitive to pemetrexed. Cell killing by pemetrexed was associated with genomic uracil accumulation, stalled DNA replication, and catastrophic DNA strand breaks. By contrast, UDG+/+ cells were \u3e10 times more resistant to pemetrexed due to the rapid removal of uracil from DNA by UDG and subsequent repair of the resultant AP sites (abasic sites) via the base excision repair (BER). The resistance to pemetrexed in UDG+/+ cells could be reversed by the addition of methoxyamine (MX), which binds to AP sites and interrupts BER pathway. Furthermore, MX-bound AP sites induced cell death was related to their cytotoxic effect of dual inactivation of UDG and topoisomerase IIα, two genes that are highly expressed in lung cancer cells in comparison with normal cells. Thus, targeting BER-based therapy exhibits more selective cytotoxicity on cancer cells through a synthetic lethal mechanism

Unexpected Role for Helicobacter pylori DNA Polymerase I As a Source of Genetic Variability

Helicobacter pylori, a human pathogen infecting about half of the world population, is characterised by its large intraspecies variability. Its genome plasticity has been invoked as the basis for its high adaptation capacity. Consistent with its small genome, H. pylori possesses only two bona fide DNA polymerases, Pol I and the replicative Pol III, lacking homologues of translesion synthesis DNA polymerases. Bacterial DNA polymerases I are implicated both in normal DNA replication and in DNA repair. We report that H. pylori DNA Pol I 5′- 3′ exonuclease domain is essential for viability, probably through its involvement in DNA replication. We show here that, despite the fact that it also plays crucial roles in DNA repair, Pol I contributes to genomic instability. Indeed, strains defective in the DNA polymerase activity of the protein, although sensitive to genotoxic agents, display reduced mutation frequencies. Conversely, overexpression of Pol I leads to a hypermutator phenotype. Although the purified protein displays an intrinsic fidelity during replication of undamaged DNA, it lacks a proofreading activity, allowing it to efficiently elongate mismatched primers and perform mutagenic translesion synthesis. In agreement with this finding, we show that the spontaneous mutator phenotype of a strain deficient in the removal of oxidised pyrimidines from the genome is in part dependent on the presence of an active DNA Pol I. This study provides evidence for an unexpected role of DNA polymerase I in generating genomic plasticity

Basin scale evolution of formation waters: a diagenetic and formation water study of the Triassic Chaunoy Formation, Paris Basin

International audienceFormation waters and their movements within basins are commonly attributed with responsibility for patterns of cementation and porosity-loss within reservoirs and aquifers. It is thus important to understand when and how waters move in the subsurface. We have studied the evolution and movement of formation water in the Triassic Chaunoy Formation of the Paris Basin, NW Europe to define the way in which the water has evolved and to interpret water movement patterns using mineral isotope and fluid inclusion data in conjunction with detailed formation water analyses. The Chaunoy Formation is cemented with different types of dolomite, calcite and quartz cement. We have studied the evolution of waters in terms of oxygen, carbon and strontium isotopes and salinity. Connate waters were meteoric in origin but strongly influenced by the proximity of a playa lake. Input of palaeo-meteoric water, which entered the Chaunoy via eastern halite bodies, resulted in highly saline formation water for the majority of the Chaunoy Formation from about 100 Ma until (and for some time after) maximum burial. Saline waters spread into the aquifer initially taking a west-north west trajectory and then switching to a west-south west pattern in the Eocene. Following the Alpine orogeny and localised uplift of the basin margin, the southern portion of Chaunoy received fresh, low salinity, meteoric water. It is likely that formation water was lost from the Chaunoy in a more central part of the basin, via sub-vertical cross formational flow to the Mid Jurassic Dogger Formation, to accommodate the influx of fresh water

Temporal behavior of a ventilated claystone at the Tournemire URL Cross-spectral analyses focused on daily harmonics

International audienceThe main topic of this communication is the presentation of study, auscultation and supervision procedures of deep geological radioactive waste storage repositories using natural harmonic forcings. In this paper, the effects of natural ventilation on the macroscopic behavior of a clayrock are investigated by means of time series recorded underground over a period of two years in the eastern part of Gallery 1996 at the Tournemire Underground Research Laboratory (URL). This study is based on time series acquired in the atmosphere, at the gallery wall surface, and inside the rock mass. It includes measured signals from 6 thermo-hygrometers, 5 crack-meters (measuring the displacement of 2 shrinkage cracks and 3 tectonic fractures), and a 1 meter-FDR (Frequency Domain Reflectometry) profile probe equipped with 6 sensors for measuring the volumetric pore-water content into the rock mass. Auto-spectral and cross-spectral analyses using the concept of Singular Spectrum Harmonics (SSHs and cross-SSHs) are developed. Our analyses and interpretations focus here mainly on the solar diurnal atmospheric tide (denoted S1). This tide corresponds to the insolation cycle of the Earth atmosphere during a mean Solar Day (24h 00min). This component is tracked throughout the various measured signals ("Spectral Tracking" of tide fluctuations across signals). This is equivalent, in a way, to analyzing the temporal behavior of the URL during a "Mean Solar Day on Earth". Results indicate that the daily natural forcing caused mainly by a combination of barometric and temperature related fluctuations, is the most important effect overall on our various signals. The daily harmonic induces the fluctuations of gallery air temperature, relative and absolute air humidity, and it leads to desaturation of the claystone, which in turn leads to the claystone deformation and damage. The effects of the annual harmonic SA may also be significant (it was fully analyzed in the more complete version of this work); however the SA results are not presented here because the spectral resolution on the annual harmonic is insufficient at this stage with only 2years and 2months of clean recorded data. Focusing the present study on daily fluctuations, the cross-spectral time shifts were obtained from the phase spectrum, for the daily component S1, for various pairs of pore-water content sensors located at different distances from the gallery wall. These time shifts were then used to quantify a "spectral velocity" which is found to be on the same order than the hydraulic conductivities deduced previously from pneumatic tests performed in the Excavation Damaged Zone of Gallery 1996. © 2014