Sudden oak death is a new disease affecting tanoak (Lithocarpus densiflora) and oaks (Quercus spp) in California and Oregon, caused by the recently described pathogen Phytophthora ramorum. It has ...reached epidemic proportions in several counties in central California, leading to the death of tens of thousands of trees. In addition to oaks and tanoak, P ramorum has been found in nearly all woody plant species in mixed evergreen and redwood forests from central California to southern Oregon. Plant species that are not killed appear to serve as a reservoir for the pathogen. The high susceptibility of tanoak to infection and death suggests that P ramorum is an exotic pathogen, but its origins, and most details of its biology and ecology, remain unknown. Our limited knowledge only compounds our concern over the long-term implications of this epidemic for the ecology of coastal forests.
1 Phytophthora ramorum (causal agent of sudden oak death) is an emerging generalist pathogen in coastal forests of California and Oregon, USA, that causes lethal stem infections on oaks (Quercus ...spp.) and tanoak (Lithocarpus densiflorus) as well as nonlethal foliar infections on a broad range of trees and shrubs. 2 We studied P. ramorum over its known range in coastal redwood forests to determine forest compositional variables that are important to its epidemiology within the geographical area that it has already invaded. Redwood forests are dominated by coast redwood (Sequoia sempervirens), tanoak and California bay laurel (Umbellularia californica). 3 A total of 120 permanent plots (500 m2 each) were established in redwood forests at 12 sites within the main epidemic area in California. Over 5000 trees were mapped and examined for the presence of P. ramorum during spring 2002 and resampled in spring 2003. 4 Mean incidence of P. ramorum across all plots was 0.17 +/- 0.01 in 2002 and 0.24 +/- 0.02 in 2003. The highest infection levels by P. ramorum were found on California bay laurel (range 0.42-0.69) and tanoak (0.32-0.45). The highest levels of mortality were associated with tanoak and ranged from 0 to 66%, with 62.5% of that mortality associated with P. ramorum infection. 5 Disease incidence above 30% was most often associated with bay laurel importance value. In plots with few bay laurel stems, high disease levels were associated with the presence of understorey tanoaks. Bay laurel and small tanoaks are thought to represent the main source of inoculum for further spread of P. ramorum. 6 Differential host mortality due to this emerging generalist pathogen will exert considerable influence on redwood forest dynamics, with potentially dramatic shifts in forest composition and structure and subsequent cascading ecological and evolutionary effects.
Recovery of Phytophthora ramorum from soils throughout sudden oak death-affected regions of California illustrates that soil may serve as an inoculum reservoir, but the role of soil inoculum in the ...disease cycle is unknown. This study addresses the efficacy of soil baiting, seasonal pathogen distribution under several epidemiologically important host species, summer survival and chlamydospore production in soil, and the impact of soil drying on pathogen survival. The efficacy of rhododendron leaves and pears as baits for detection of soilborne propagules were compared. Natural inoculum associated with bay laurel (Umbellularia californica), tanoak (Lithocarpus densiflorus), and redwood (Sequoia sempervirens) were determined by monthly baiting. Summer survival and chlamydospore production were assessed in infected rhododendron leaf disks incubated under bay laurel, tanoak, and redwood at either the surface, the litter/soil interface, or in soil. Rhododendron leaf baits were superior to pear baits for sporangia detection, but neither bait detected chlamydospores. Most inoculum was associated with bay laurel and recovery was higher in soil than litter. Soil-incubated inoculum exhibited over 60% survival at the end of summer and also supported elevated chlamydospore production. P. ramorum survives and produces chlamydospores in forest soils over summer, providing a possible inoculum reservoir at the onset of the fall disease cycle.
In this paper, we address methods of multivariate regression. We discuss the value of regression compared to matched pairs analysis, methods of coding variables, basic concepts of the Cox model and ...interpretation of results of the Cox model. We present methods of handling variables whose effect changes with time. We present methods to check the assumptions of the Cox regression. Finally, and perhaps most importantly, we provide suggestions for presenting the results in clear and thorough tables and graphs.
Ripersiella hibisci (Kawai & Takagi, 1971) is a root mealybug included in the EPPO A1 list of pests recommended for regulation and an EU A1 Quarantine pest list (Annex IIA). This pest causes damage ...to several species of monocotyledonous and dicotyledonous ornamental and foliage potted plants, especially bonsais. The underground location of R. hibisci makes its detection difficult during phytosanitary controls, and moreover, it can be confused with other non‐regulated species of mealybugs (e.g. Planococcus citri, P. ficus, Rhizoecus falcifer, Rhizoecus dianthi). Thus, a molecular test based on real‐time PCR was designed for rapid and unambiguous identification of this mealybug. Analytical sensitivity, analytical specificity, repeatability and reproducibility of the test were assessed as part of the validation. The test showed 100% analytical specificity (exclusivity and inclusivity), allowing the target to be distinguished from all non‐target species tested (exclusivity); the inclusivity was demonstrated, validating the test on different populations of the pest. The molecular test is an efficient tool for the identification of the root mealybug R. hibisci (in its various life stages), which is particularly useful when a rapid screening of samples is needed to limit or avoid the introduction of the pest.
Identification rapide de Ripersiella (= Rhizoecus) hibisci (Kawai & Takagi, 1971) (Hemiptera: Rhizoecidae) grâce à la PCR en temps réel avec une sonde TaqMan
Ripersiella hibisci (Kawai & Takagi, 1971) est une cochenille des racines incluse dans la liste A1 de l’OEPP des organismes nuisibles recommandés pour réglementation, et dans une liste A1 de l'Union européenne d'organismes nuisibles de quarantaine (Annexe II A). Cet organisme nuisible cause des dommages à plusieurs espèces de plantes ornementales et à feuillage en pots, monocotylédones et dicotylédones, notamment les bonsaïs. La localisation souterraine de R. hibisci rend sa détection difficile lors des contrôles phytosanitaires, et elle peut également être confondue avec d'autres espèces de cochenilles non réglementées (par exemple Planococcus citri, P. ficus, Rhizoecus falcifer, Rh. dianthi). Ainsi, un test moléculaire basé sur la PCR en temps réel a été conçu pour une identification rapide et sans ambiguïté de cette cochenille. La sensibilité et spécificité analytiques, la répétabilité et la reproductibilité du test ont été évaluées dans le cadre de la validation. Le test a montré 100 % de spécificité analytique (exclusivité et inclusivité), permettant de distinguer la cible de toutes les espèces non‐cibles testées (exclusivité). L'inclusivité a été démontrée en validant le test sur différentes populations de l'organisme nuisible. Ce test moléculaire est un outil efficace pour l'identification de la cochenille des racines R. hibisci (à différents stades de vie), ce qui est particulièrement utile lorsqu'un dépistage rapide des échantillons est nécessaire pour limiter ou éviter l'introduction de cet organisme nuisible.
Быстрое выявление гибискусового корневого червеца Ripersiella (= Rhizoecus) hibisci (Kawai & Takagi, 1971) (Hemiptera: Rhizoecidae) с помощью РВ‐ПЦР и зондов TaqMan
Ripersiella hibisci (Kawai & Takagi, 1971) – корневой мучнистый червец, включенный в А1 список вредных организмов ЕОКЗР, рекомендованных для регулирования, а также в карантинный список А1 вредных организмов ЕС (Приложение II A). Этот вредитель повреждает несколько видов однодольных и двудольных декоративных горшечных растений, особенно бонсаи. Развитие R. hibisci под землей затрудняет его выявление при фитосанитарном контроле. Кроме того, его можно спутать с другими нерегулируемыми видами мучнистых червецов (например, Planococcus citri, P. ficus, Rhizoecus falcifer, Rh. dianthi). Таким образом, для быстрой и однозначной видовой идентификации этого мучнистого червеца был разработан молекулярный тест на основе ПЦР в режиме реального времени. В рамках валидации теста оценивались его аналитическая чувствительность, аналитическая специфика, повторяемость и воспроизводимость. Тест показал 100% аналитическую специфичность (исключительность и инклюзивность), что позволило отличить R. hibisci, на которого нацелен тест, от всех остальных протестированных нецелевых видов (эксклюзивность); инклюзивность была продемонстрирована при валидации теста на различных популяциях вредного организма. Молекулярный тест является эффективным инструментом для видовой идентификации корневого мучнистого червеца R. hibisci на различных стадиях его развития, что особенно полезно при необходимости быстрого скрининга образцов для ограничения или предотвращения интродукции вредного организма.
Introduction. The use of equine bone blocks is widely reported for bone augmentation techniques. The block must be shaped according to the form of the defect that should be regenerated. The shaping ...could be performed by hand before or during the surgery, in a sterile ambient, or using a CNC milling machine that could not be sterile. The aim of our study was to evaluate if a steam sterilization could provide a medical grade sterilization of the blocks and to evaluate if bone microstructure and collagen structures change after different steam sterilization protocols provided by mainstream autoclave. Materials and Method. Two blocks of equine bone were divided into 16 samples. 1 sample was used as control and not submitted to any treatment. 15 samples were infected with a Streptococcus faecalis bacterial culture. The samples were singularly packed, randomly divided into 3 groups, and submitted to autoclave sterilization on the same device. The groups were submitted to a sterilization cycle (Gr. A: 121°C, 1,16 bar for 20′; Gr. B:134°C, 2,16 bar for 4′; Gr. C: 134°C, 2,16 bar for 3.30 min.). 2 samples for each group were evaluated for the sterility. 3 samples for each group were observed at SEM to notice the macro- and microstructure modification and to confocal microscope to observe the collagen. Results. All samples were sterile. The SEM evaluation showed, in all groups, a preserved morphological structure. Confocal microscope evaluation shows that the collagen structure appears to be more uniform and preserved in group C. Conclusion. Data show that autoclave steam sterilization could be reliable to obtain sterilization of equine bone blocks.
Spartium junceum
L. is a typical species of Mediterranean shrubland areas, also grown in gardens and parks as an ornamental. In recent years in Europe,
S. junceum
has been recurrently found to be ...infected by different subspecies and genotypes of the quarantine regulated bacterium
Xylella fastidiosa
(Xf). This work presents for the first time the anatomy of
S. junceum
plants that we found, by means of genetic and immunochemistry analysis, to be naturally infected by Xf subsp.
multiplex
ST87 (XfmST87) in Monte Argentario (Grosseto, Tuscany, Italy), a new outbreak area within the EU. Our anatomical observations showed that bacteria colonized exclusively the xylem conductive elements and moved horizontally to adjacent vessels through pits. Interestingly, a pink/violet matrix was observed with Toluidine blue staining in infected conduits indicating a high content of acidic polysaccharides. In particular, when this pink-staining matrix was observed, bacterial cells were either absent or degenerated, suggesting that the matrix was produced by the host plant as a defense response against bacterial spread. In addition, a blue-staining phenolic material was found in the vessels and, at high concentration, in the pits and inter-vessels. SEM micrographs confirmed that polysaccharide and phenolic components showed different structures, which appear to be related to two different morphologies: fibrillary and granular, respectively. Moreover, our LM observations revealed bacterial infection in xylem conductive elements of green shoots and leaves only, and not in those of other plant organs such as roots and flowers.
Magnetoresistive random access memory (MRAM) technology combines a spintronic device with standard silicon-based microelectronics to obtain a combination of attributes not found in any other memory ...technology. Key attributes of MRAM technology are nonvolatility and unlimited read and write endurance. Magnetic tunnel junction (MTJ) devices have several advantages over other magnetoresistive devices for use in MRAM cells, such as a large signal for the read operation and a resistance that can be tailored to the circuit. Due to these attributes, MTJ MRAM can operate at high speed and is expected to have competitive densities when commercialized. In this paper, we review our recent progress in the development of MTJ-MRAM technology. We describe how the memory operates, including significant aspects of reading, writing, and integration of the magnetic material with CMOS, which enabled our recent demonstration of a 1-Mbit memory chip. Important memory attributes are compared between MRAM and other memory technologies.
The VIMOS VLT Deep Survey (VVDS), designed to measure 150,000 galaxy redshifts, requires a dedicated data reduction and analysis pipeline to process in a timely fashion the large amount of ...spectroscopic data being produced. This requirement has lead to the development of the VIMOS Interactive Pipeline and Graphical Interface (VIPGI), a new software package designed to simplify to a very high degree the task of reducing astronomical data obtained with VIMOS (Visible Multi–Object Spectrograph), the imaging spectrograph built by the VIRMOS Consortium for the European Southern Observatory and mounted on Unit 3 (Melipal) of the VLT (Very Large Telescope) at Paranal Observatory (Chile). VIPGI provides the astronomer with specially designed VIMOS data‐reduction functions, a VIMOS‐centric data organizer, and dedicated data browsing and plotting tools, which can be used to verify the quality and accuracy of the various stages of the data‐reduction process. The quality and accuracy of the data‐reduction pipeline are comparable to those obtained using well‐known IRAF tasks, but the speed of the data‐reduction process is significantly increased, because of the dedicated nature of VIPGI. In this paper we discuss the details of the multiobject spectroscopy (MOS) data‐reduction pipeline that has been implemented in VIPGI, as applied to the reduction of some 20,000 VVDS spectra, quantitatively assessing the accuracy of the various reduction steps. We also provide a more general overview of VIPGI capabilities, a tool that can be used for the reduction of any kind of VIMOS data.
Le syndrome hyperéosinophilique essentiel (SHE) a été défini pour la première fois par Chusid et al., en 1975 1. Au fil du temps, cette entité s’est divisée en plusieurs sous-groupes en fonction de ...la physiopathologie 2. La recherche du phénotype T aberrant par cytométrie en flux (CMF) et la recherche de clonalité par PCR sont nécessaires au diagnostic du SHE variant lymphoïde (SHE-L) 3. La CMF utilise un panel composé en général d’une dizaine d’anticorps d’anti-cluster de différenciation (CD). Du fait de nombreux phénotypes T anormaux décrits dans la littérature, les panels d’anticorps dirigés contre les marqueurs de surface utilisés sont variables d’un laboratoire à l’autre, sans être standardisés.
Il s’agit d’une étude rétrospective, monocentrique menée de 2005 à 2016, incluant les patients diagnostiqués comme SHE idiopathique (SHE-I) et SHE-L. Les données cliniques, biologiques ainsi que la réponse au traitement ont été recueillis. Les résultats de la CMF et de la clonalité ont été relus par 2 investigateurs. L’hypothèse était la présence du variant lymphoïde parmi les SHE-I. L’objectif était d’évaluer l’apport diagnostique de la CMF à l’aide d’un seul panel d’anticorps d’anti-CD utilisé, dans la détection des phénotypes T aberrants définissant le SHE-L. Les objectifs secondaires étaient d’évaluer la place de la clonalité T et de la pertinence des examens complémentaires autres dans le diagnostic du SHE-L.
Sur une période de 10 ans, les dossiers de 518 patients ayant consulté pour une hyperéosinophilie dans les services d’hématologie et de médecine interne du C.H.U. de Limoges ont été analysés. Seuls 20 patients au diagnostic de SHE-I (n=12) et SHE-L (n=8) ont été inclus. La comparaison des deux groupes SHE-I et SHE-L, n’a pas mis en évidence de différence clinique, biologique, ou réponse thérapeutique. L’apparition du phénotype aberrant a été notée au cours du suivi chez deux patients. La comparaison des groupes traité versus non traité a mis en évidence que les patients traités étaient plus altérés (p=0,03), avec une hyperéosinophilie plus marquée (p=0,029). Les examens invasifs tels que le myelogramme et la biopsie ostéo-médullaire étaient soit normaux, soit mettaient en évidence une hyperéosinophilie sans dystrophie ni autre anomalie, n’apportant donc aucune contribution diagnostique dans le SHE-L.
En dehors du phénotype aberrant et de la clonalité, le groupe SHE-L est habituellement caractérisé par des manifestations cutanées associées à un taux élevé d’IgE, une hypergammaglobulinémie polyclonale et une importante cortico-sensibilité. La comparaison du groupe SHE-L et du SHE-I a abouti à 2 profils identiques sans différence en termes du terrain, de la présentation clinico-biologique et de la réponse au traitement. Ce travail permet d’émettre plusieurs hypothèses sur l’imperfection de la CMF : il est possible qu’un seul panel ne soit pas à lui seul suffisant pour diagnostiquer avec certitude tous les phénotypes aberrants. L’analyse de la CMF peut s’avérer compliquée dans certains cas rendant ainsi la coopération biologiste–clinicien indispensable. Le pourcentage des lymphocytes T ayant un phénotype T aberrant est arbitraire et non standardisé.
La présence des SHE-L non détectés à l’aide d’un seul panel d’anti-CD, parmi les SHE-I semble plausible. Afin de vérifier cette hypothèse, il serait intéressant de mener une étude comparative entre le panel classique utilisé par le laboratoire et un autre, plus étendu, pour les patients au profil clinique du SHE-L avec une altération de l’état général et n’ayant pas de phénotype aberrant dépisté par le panel classique. Pour cela, il est important de définir les CD les plus pertinents d’une part du fait du coût des anticorps et d’autre part pour essayer de déterminer un maximum de phénotypes aberrants. L’apparition du phénotype T aberrant au cours du suivi suggère un continuum entre ces deux entités.
PDF
