Pierce's Disease of Grapevines: Identification of the Primary Vectors in North Carolina

ABSTRACT In the past 10 years, the winegrape industry in the southeastern United States has experienced rapid growth; however, further expansion may be inhibited by Pierce's disease (PD). Epidemiological studies were conducted to identify the primary vectors of Xylella fastidiosa, the cause of PD of grape, by surveying sharpshooter population dynamics in the eastern Piedmont and Coastal Plain regions of North Carolina. Sharpshooter species were assessed for the presence of X. fastidiosa in the field. Leafhoppers were trapped in three vineyards in the eastern Piedmont and one vineyard in the northeastern Coastal Plain in 2004 and 2005. Four insects were identified as most abundant: Oncometopia orbona, Graphocephala versuta, Paraphlepsius irroratus, and Agalliota constricta. Adult specimens of O. orbona, G. versuta, and P. irroratus were tested for the presence of X. fastidiosa by nested polymerase chain reaction. In all, 27% of O. orbona, 28% of G. versuta, and 33% of P. irroratus trapped were positive for X. fastidiosa over the two seasons. Transmission experiments demonstrated that both O. orbona and G. versuta have the ability to transmit X. fastidiosa to grape. These vectors are likely to be important in all winegrowing regions of the Southeast, because their presence has been documented throughout the southern states. In DNA analyses, X. fastidiosa strains from insects trapped in North Carolina were genetically similar to one another and to the known "PD strain" from California. This is the first report of these two leafhopper species transmitting X. fastidiosa to grapevines in the Southeast.     

Plant age and timing of epidemic initiation affect mycosphaerella blight in field pea

Journal of Plant Diseases and Protection - Mycosphaerella blight (Mycosphaerella pinodes) occurs throughout western Canada and can severely reduce seed yield and quality of field pea (Pisum...     

Single reconstituted neuronal SNARE complexes zipper in three distinct stages

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins drive membrane fusion by assembling into a four-helix bundle in a zippering process. Here, we used optical tweezers to observe in a cell-free reconstitution experiment in real time a long-sought SNARE assembly intermediate in which only the membrane-distal amino-terminal half of the bundle is assembled. Our findings support the zippering hypothesis, but suggest that zippering proceeds through three sequential binary switches, not continuously, in the amino- and carboxyl-terminal halves of the bundle and the linker domain. The half-zippered intermediate was stabilized by externally applied force that mimicked the repulsion between apposed membranes being forced to fuse. This intermediate then rapidly and forcefully zippered, delivering free energy of 36 k(B)T (where k(B) is Boltzmann's constant and T is temperature) to mediate fusion.     

Terrestrial movements and habitat use of gopher frogs in longleaf pine forests: A comparative study of juveniles and adults

Many animals exhibit changes in patterns of movement and habitat use as they age, and understanding such ontogenetic shifts is important for ensuring that habitat management is appropriate for all life stages. We used radiotelemetry to study movements and habitat use of juvenile and adult gopher frogs (Rana capito) as they migrated from the same ponds following metamorphosis or breeding. To supplement radiotelemetry data, we also captured adult gopher frogs at drift fences as they left ponds for the terrestrial environment. We directly compared patterns of movement, directional orientation, macrohabitat use (forest type), and microhabitat use (refugia) between the two life stages. Both juveniles and adults moved considerable distances from breeding ponds (up to 691 m) and selected fire-maintained longleaf pine (Pinus palustris) forest over fire-suppressed forest. However, fire-suppressed habitat appeared to be a greater barrier to juveniles than adults. Additionally, we found differences in microhabitat use; both juveniles and adults used underground refuges (e.g., burrows and stump holes) for shelter, but juveniles used such refuges less often than adults. Juveniles also took more time than adults to locate their first refuge after exiting ponds. These differences may reflect the juveniles’ lack of experience in terrestrial habitats. Unlike juveniles, adults are likely more familiar with the locations of specific habitat features (e.g., burrows and ponds) and may take the shortest routes when moving among them, even if it requires moving through fire-suppressed habitat. Previous research has recommended that terrestrial habitats surrounding breeding ponds should be managed with frequent prescribed fire (i.e., 1–3-year intervals) in order to maintain suitable terrestrial habitat for juvenile gopher frogs, and our study suggests that these management practices are also likely beneficial to adults.     

Spatial Relations between Row Crops and Nitrate Contamination in Groundwater

Nitrogen management practices associated with row crops arewidely considered as an important contributor to nitrate pollution in water resources. We studied the relations between row crops and nitrate concentration in groundwater in an agricultural basin of Iowa, U.S.A., from a spatial perspective. Nitrate concentration and row crop area wereanalyzed on a section scale (a square mile, or 2.56 km²)for three different years. Their section values were standardized to remove the effects of precipitation and non-constant sample variances in different years. The between-year differences in individual section values werecollectively analyzed as an indication of changes in the spatial distribution from year to year. Contingency table analysis was applied to test for relations of spatial changesbetween nitrate and row crops. During the study period, thenitrate concentration and row crop area on a per section basischanged considerably from one sampling year to another.However, no significant changes were found in their spatial distributions. As a result, no significant relations betweennitrate and row crops were found in terms of changes in theirspatial distributions.     

In Vitro Biomechanical Comparison of a Modified 5.5 mm Locking Compression Plate Fixation with a 5.5 mm Locking Compression Plate Fixation of Osteotomized Equine Third Metacarpal Bones

Objectives: To compare number of cycles to failure for palmarodorsal 4‐point bending of a modified 5.5 mm broad locking compression plate (M5.5‐LCP) fixation with a 5.5 mm broad LCP (5.5‐LCP) fixation used to repair osteotomized equine third metacarpal (MC3) bones. Study Design: In vitro biomechanical testing. Animal Population: Adult equine cadaveric MC3 bones (n=6 pairs). Methods: An 8‐hole, M5.5‐LCP, obtained by having a 1.0 mm thickness removed from the bone contact portion of the 5.5‐LCP, was applied to the dorsal surface of 1 randomly selected MC3 from each pair, and an 8‐hole, 5.5‐LCP was applied dorsally to the contralateral bone from each pair using a combination of cortical and locking screws. Plates and screws were applied using standard ASIF techniques to MC3 bones with a mid‐diaphyseal osteotomy. MC3 constructs had palmarodorsal 4‐point bending cyclic fatigue testing. Mean cycles to failure for each method were compared using a paired t‐test within each group. Significance was set at P<.05. Results: Mean±SD cycles to failure of the M5.5‐LCP fixation (188,641±17,971) was significantly greater than that of the 5.5‐LCP fixation (166,497±15,539). Conclusion: M5.5‐LCP fixation was superior to 5.5‐LCP fixation of osteotomized equine MC3 bones in resisting cyclic fatigue under palmarodorsal 4‐point bending. Clinical Relevance: This suggests that biological plate fixation is not the ideal choice for osteotomized equine MC3 bones.     

Preliminary studies on growth and fresh weight of lettuce (Lactuca sativa) as affected by clay pot irrigation and spacing

An experiment (Completely Randomized Design) was set up to determine the effects of Clay Pot Sub-surface Irrigation (CPSI) and spacing on the growth and fresh weight of lettuce (Lactuca sativa). The treatments were: CPSI with spacing; 15 x 15 cm, 20 x 20 cm and 30 x 30 cm. Control treatments were Watering Can Irrigation (WCI) with the same spacing as above. Treatments were replicated three times given a total of 18 experimental units. Eighteen large enamel basins of 50/20 cm (diameter/height) were filled with good topsoil and a clay pot buried neck deep in each of the basins. Seedlings were planted in all the eighteen basins. Five Hundred mL of wastewater was applied daily to plants in each container having either clay pot or watering can treatment. Plant height increased from 2.50 to 4.25 cm within 6 Weeks after Transplanting (WAT) under CPSI and only increased from 2.14 to 2.99 cm under WCI. The CPSI also supported better leave growth and fresh weight. The fresh weight of lettuce increased almost two fold under 15 x 15 cm spacing compared to 20 x 20 and 30 x 30 cm.     

Monitoring Sensitivity to Land Degradation and Desertification with the Environmentally Sensitive Area Index: The Case of Lesvos Island

In Europe, the most susceptible areas to land degradation and desertification (LDD) are found in the Mediterranean region. The present study focuses on the island of Lesvos (Greece) and maps the environmental sensitivity of the island to LDD between the years 1990 and 2000. Sensitivity is estimated with a modification of the MEDALUS Environmentally Sensitive Area Index (ESAI) approach, employing 21 quantitative parameters divided in five main quality indices: climate, vegetation, soils, groundwater and socio‐economic quality. Parameterisation of these indices is achieved via remote sensing and ancillary data in a Geographical Information System (GIS). Results show that ~85% of the island is fragile or critically sensitive in both epochs. Fragile areas are on the increase, covering an estimated 72% of the island in 1990 and 77% in 2000, whereas critically sensitive areas decrease from 214 to 113 km². By modifying the ESAI to include 10 additional parameters related to soil erosion, groundwater quality, demographic and grazing pressure, and by applying the modified ESAI in two—rather than one—periods, this study was able to identify that, contrary to previous belief, critically sensitive areas are also found in the eastern side of the island mainly due to human‐related factors. It is concluded that the proposed methodology is a useful tool for regional scale trend analyses of environmental sensitivity and the identification of LDD hot spots in Mediterranean environments. Copyright © 2014 John Wiley & Sons, Ltd.     

An investigation into the potential use of nanoparticles as adjuvants for the production of polyclonal antibodies to low molecular weight compounds

Two nanoparticle based adjuvants were assessed for their ability to produce polyclonal antibodies in rabbits to low molecular weight target analytes, i.e. veterinary drugs banned from use in food producing animals. The nanoparticles, Montanide IMS 251 and amphiphilic poly (γ-glutamic acid) were compared against a mineral oil adjuvant, Montanide ISA 50, which had previously been shown to be successful in producing antibodies to haptens whilst being safe to use with respect to the welfare of the host animals. The adjuvants were assessed for their tendency to cause adverse effects to the host animals and by the quality of the antibodies generated in terms of assay sensitivity. None of the three adjuvants employed in the trial generated any measurable adverse effects in the host animals. While the mineral oil adjuvant produced higher titres of antibodies the nanoparticle adjuvants were found to produce antibodies of statistically comparable sensitivity. Based on IC(50) values, six antisera displayed potential to detect the required level of the target compounds; five of these were produced by rabbits immunised with the two different nanoparticle adjuvants. As antibody sensitivity is the main performance criteria of an analytical immunoassay, it can be concluded that the nanoparticle adjuvants under evaluation are fit for the purpose described in this study.