A new symptomatology was observed in celery (Apium graveolens) in Villena, Spain in 2008. Symptomatology included an abnormal amount of shoots per plant and curled stems. These vegetative disorders were associated with 'Candidatus Liberibacter solanacearum' and not with phytoplasmas. Samples from plant sap were immobilized on membranes based on the spot procedure and tested using a newly developed real-time polymerase chain reaction assay to detect 'Ca. L. solanacearum'. Then, a test kit was developed and validated by intralaboratory assays with an accuracy of 100%. Bacterial-like cells with typical morphology of 'Ca. Liberibacter' were observed using electron microscopy in celery plant tissues. A fifth haplotype of 'Ca. L. solanacearum', named E, was identified in celery and in carrot after analyzing partial sequences of 16S and 50S ribosomal RNA genes. From our results, celery (family Apiaceae) can be listed as a new natural host of this emerging bacterium.

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ABSTRACTin oxidation states. Sulfur occurs in soil both in organic and inorganic forms. However, most of the soil S Sulfur K-edge X-ray absorption spectroscopy (XANES) was used (Ͼ95%) in temperate and tropical ecosystems is present to identify S oxidation states and assess the impact of land use changes on the amount, form, and distribution of organic S in particle-size in organic forms (Janzen and Ellert, 1998; separates and their humic substance extracts. Soil samples (0-10 cm)1998; Solomon et al., 2001a tempted to speciate S into its functional groups using follow its dynamics in terrestrial ecosystems.pyrolysis gas chromatography mass spectrometry in aquatic humic substances (Van Loon et al., 1993) and kerogens (Carmo et al., 1997) for characterization of S ulfur is a highly reactive element, existing in several S containing moieties, but this approach is limited to oxidation states and moving freely among the lithospeciation of thermally stable forms of S (Hundal et sphere, hydrosphere, and atmosphere. The accumulaal., 2000). tion and cycling of S are central to many biological Synchrotron-based S K-edge XANES spectroscopy processes and provide a key to understanding changes in has been successfully used to speciate and quantify all the biosphere. Sulfur cycling also significantly influences oxidation states of S in a variety of geochemical samples atmospheric and oceanic chemistry and the global enranging from petroleum (Waldo et al., 1991a,b), coal ergy balance. Therefore, the chemistry of S compounds (Huffman et al., 1995), marine sediments (Vairavamurin the environment has taken on a new significance in thy et al., 1993, 1994), biosolids (Hundal et al., 2000) to recent years because human activities have dramatically soil humic and fulvic acids (Morra et al., 1997; Xia et altered the biogeochemical S cycling in terrestrial ecoal., 1998; Szulczewski et al., 2001). X-ray absorption systems.near-edge structure spectroscopy has also proven to be The soil environment is the primary component of a valuable tool in the identification and quantification the global biogeochemical S cycle, acting as a source of S oxidation states in organic soils (Martínez et al., and sink for various S species and mediating changes 2002 need to conduct comparative studies that involve land cm. Crop residues that remain on the fields are normally use changes, which may help to describe important reaccollected and used as animal feed at both sites.tions of S to long-term management changes. This techWe selected three representative fields from each land use system. After considering the depth of cultivation to minimize nique can be combined with physical fractionation of differences, which may arise due to the dilution of SOM from soil according to particle-size separates, which has been mixing of the surface soil with the subsoil through cultivation, demonstrated to provide ecologically meaningful soil S we used a core sampler (200 cm 3 core volume) and collected pools (Solomon et al., 2001a). Thus, S K-edge XANES nine subsample...

A protocol for the specific detection and quantification of ‘Candidatus Liberibacter solanacearum’ in carrot seeds using real‐time PCR was developed. The bacterium was detected in 23 out of 54 carrot seed lots from 2010 to 2014, including seeds collected from diseased mother plants. The average total number of ‘Ca. L. solanacearum’ cells in individual seeds ranged from 4·8 ± 3·3 to 210 ± 6·7 cells per seed from three seed lots, but using propidium monoazide to target live cells, 95% of the cells in one seed lot were found to be dead. Liberibacter‐like cells were observed in the phloem sieve tubes of the seed coat and in the phloem of carrot leaf midrib from seedlings. The bacterium was detected as early as 30 days post‐germination, but more consistently after 90 days, in seedlings grown from PCR positive seed lots in an insect‐proof P2 level containment greenhouse. Between 12% and 42% of the seedlings from positive seed lots tested positive for ‘Ca. L. solanacearum’. After 150 days, symptoms of proliferation were observed in 12% of seedlings of cv. Maestro. ‘Candidatus Liberibacter solanacearum’ haplotype E was identified in the seeds and seedlings of cv. Maestro. No phytoplasmas were detected in seedlings with symptoms using a real‐time assay for universal detection of phytoplasmas. The results show that to prevent the entry and establishment of the bacterium in new areas and its potential spread to other crops, control of ‘Ca. L. solanacearum’ in seed lots is required.

The purpose of this study was to compare the effect of nutritional intake during tooth-crown formation on the subsequent development of linear enamel hypoplasias (LEHs) in Mexican nonsupplemented (control) adolescents (n = 42) and adolescents who had received daily nutritional supplements since birth (n = 42). The proportion of individuals with LEHs was nearly two-fold greater (74.4%; 95% CI 64.7-84.1%) in the control than in the supplemented group (39.5%; 95% CI 28.6-50.4%; chi 2 = 9.44; P = 0.001). Although the estimated peak age at formation, approximately 2-2.5 y, is similar in both groups, the proportion of early (before 1.5 y) and late (after 3.0 y) LEHs was greater in the control group. LEH was also more common in females and was associated with an increase in illness days and a decrease in growth velocity. Results of this study suggest that mild to moderate undernutrition during enamel formation is causally linked to the formation of LEHs.