Full methylation of H3K27 by PRC2 is dispensable for initial embryoid body formation but required to maintain differentiated cell identity

Polycomb repressive complex 2 (PRC2) catalyzes methylation of histone H3 on lysine 27 and is required for normal development of complex eukaryotes. The nature of that requirement is not clear. H3K27me3 is associated with repressed genes, but the modification is not sufficient to induce repression and, in some instances, is not required. We blocked full methylation of H3K27 with both a small molecule inhibitor, GSK343, and by introducing a point mutation into EZH2, the catalytic subunit of PRC2, in the mouse CJ7 cell line. Cells with substantively decreased H3K27 methylation differentiate into embryoid bodies, which contrasts with EZH2 null cells. PRC2 targets had varied requirements for H3K27me3, with a subset that maintained normal levels of repression in the absence of methylation. The primary cellular phenotype of blocked H3K27 methylation was an inability of altered cells to maintain a differentiated state when challenged. This phenotype was determined by H3K27 methylation in embryonic stem cells through the first 4 days of differentiation. Full H3K27 methylation therefore was not necessary for formation of differentiated cell states during embryoid body formation but was required to maintain a stable differentiated state.

Ataxin-7 and Non-stop coordinate SCAR protein levels, subcellular localization, and actin cytoskeleton organization

Atxn7, a subunit of SAGA chromatin remodeling complex, is subject to polyglutamine expansion at the amino terminus, causing spinocerebellar ataxia type 7 (SCA7), a progressive retinal and neurodegenerative disease. Within SAGA, the Atxn7 amino terminus anchors Non-stop, a deubiquitinase, to the complex. To understand the scope of Atxn7-dependent regulation of Non-stop, substrates of the deubiquitinase were sought. This revealed Non-stop, dissociated from Atxn7, interacts with Arp2/3 and WAVE regulatory complexes (WRC), which control actin cytoskeleton assembly. There, Non-stop countered polyubiquitination and proteasomal degradation of WRC subunit SCAR. Dependent on conserved WRC interacting receptor sequences (WIRS), Non-stop augmentation increased protein levels, and directed subcellular localization, of SCAR, decreasing cell area and number of protrusions. In vivo, heterozygous mutation of SCAR did not significantly rescue knockdown of Atxn7, but heterozygous mutation of Atxn7 rescued haploinsufficiency of SCAR.

Mechanisms of and variables affecting UVR photoadaptation in human skin

Humans have been exposed to solar UV radiation since their appearance on Earth and evolution has enabled most individuals to adapt to this exposure, to some degree. UV radiation produces several deleterious effects in human skin and light-skinned individuals are at greatest risk for both acute and long-term negative effects such as DNA damage, sunburn, immune suppression and skin cancer. The benefits of photoadaptation, which leads to a decreased response after acclimatization, are that humans who have skin that is capable of photoadaptation can work and play in the sun with reduced fear of painful sunburn. However, the effects of photoadaptation on DNA damage and development of skin cancer are quite complex and less well-understood. In this article, we have reviewed the current state of knowledge of UVR photoadaptation in human skin. However, more studies are needed to explore the use of UVR photoadaptation to protect against critical endpoints, such as skin cancer.

The association between antibiotic use in infancy and childhood overweight or obesity: a systematic review and meta-analysis

PURPOSE

Antibiotic use is associated with alteration of the gut microbiome and metabolic activity. As childhood obesity is a predisposing factor for adult obesity, addressing childhood risk factors to weight gain in early life is important. This review aims to investigate the association between infant antibiotic exposure (aged < 24 months) and childhood obesity or overweight.

METHODS

Articles were retrieved from CINAHL, Cochrane CENTRAL, Embase and MEDLINE. Eligible articles investigated antibiotic use in exposed versus unexposed infants and measured childhood weight change. Data were synthesized narratively and meta-analysed where possible.

RESULTS

After title/abstract and full-text screening, 17 articles representing 15 unique studies were included for narrative synthesis. We found a small association between antibiotic exposure in infancy (<24 months) and childhood overweight or obesity. The strongest associations were observed in boys versus girls and children exposed to multiple antibiotic courses or broad-spectrum drugs. Meta-analysis of 12 sets of results comparing the earliest age of exposure to any antibiotic with overweight or obesity at the latest age of outcome found a pooled odds ratio of 1.05 (95% confidence interval: 1.00-1.11).

CONCLUSIONS

Antibiotic exposure in infants, aged < 24 months, was associated with a small increase in odds of childhood overweight or obesity in some subgroups of children.

Predicting the risk of cucurbit downy mildew in the eastern United States using an integrated aerobiological model

Cucurbit downy mildew caused by the obligate oomycete, Pseudoperonospora cubensis, is considered one of the most economically important diseases of cucurbits worldwide. In the continental United States, the pathogen overwinters in southern Florida and along the coast of the Gulf of Mexico. Outbreaks of the disease in northern states occur annually via long-distance aerial transport of sporangia from infected source fields. An integrated aerobiological modeling system has been developed to predict the risk of disease occurrence and to facilitate timely use of fungicides for disease management. The forecasting system, which combines information on known inoculum sources, long-distance atmospheric spore transport and spore deposition modules, was tested to determine its accuracy in predicting risk of disease outbreak. Rainwater samples at disease monitoring sites in Alabama, Georgia, Louisiana, New York, North Carolina, Ohio, Pennsylvania and South Carolina were collected weekly from planting to the first appearance of symptoms at the field sites during the 2013, 2014, and 2015 growing seasons. A conventional PCR assay with primers specific to P. cubensis was used to detect the presence of sporangia in rain water samples. Disease forecasts were monitored and recorded for each site after each rain event until initial disease symptoms appeared. The pathogen was detected in 38 of the 187 rainwater samples collected during the study period. The forecasting system correctly predicted the risk of disease outbreak based on the presence of sporangia or appearance of initial disease symptoms with an overall accuracy rate of 66 and 75%, respectively. In addition, the probability that the forecasting system correctly classified the presence or absence of disease was ≥ 73%. The true skill statistic calculated based on the appearance of disease symptoms in cucurbit field plantings ranged from 0.42 to 0.58, indicating that the disease forecasting system had an acceptable to good performance in predicting the risk of cucurbit downy mildew outbreak in the eastern United States.

Tailoring 2D and 3D molecular sieves structures for polyolefin composites: do all roads lead to remarkable performances?

Multiple synthetic strategies were performed in order to tether a zirconium-based catalyst to the 2D and 3D molecular sieves for olefin polymerizations. The anchoring of fluorene silane to the mesoporous MCM-41 was performed in order to obtain a stable catalyst for olefin polymerization (1@MCM-41). Using spectroscopic methods, this system was shown to have the metal center locked on a face down conformation with the surface. Also, immobilized zirconium complexes have been prepared on three different types of aminopropyl-modified supports (2@magadiite, 2@MCM-41 and 3@MCM-48). The advantage of this latter method of immobilization would be the reduction of the steric effect caused by the support: the catalyst, distant from the surface, is more exposed to the monomer and this situation may lead to an increase in the catalytic activity compared to 1@MCM-41. However, a medium size chain as a spacer between the support and the metallocene is still flexible enough to bend and predisposes the metal center to interact with the support surface; this effect is more evident when the nature of the support is of fixed pore dimensions. These supported catalysts exhibited activity for ethylene polymerization, resulting in linear PEs with high melting temperatures. In order to retain a metallocene assembled as in a homogeneous environment, a multi-step reaction was investigated (4@magadiite) but it led to the leaching of the organic moieties from the surface during catalyst preparation. The best catalytic performance was achieved when homogeneous Oct-amido catalyst (5) was reacted with the surface of magadiite and n-alkyl-AlPO-kan.

Evaluation of Oxacillin and Cefoxitin Disk Diffusion and MIC Breakpoints Established by the Clinical and Laboratory Standards Institute for Detection of mecA-Mediated Oxacillin Resistance in Staphylococcus schleiferi

Staphylococcus schleiferi is a beta-hemolytic, coagulase-variable colonizer of small animals that can cause opportunistic infections in humans. In veterinary isolates, the rate of mecA-mediated oxacillin resistance is significant, with reported resistance rates of >39%. The goal of this study was to evaluate oxacillin and cefoxitin disk diffusion (DD) and MIC breakpoints for detection of mecA-mediated oxacillin resistance in 52 human and 38 veterinary isolates of S. schleiferi Isolates were tested on multiple brands of commercial media and according to Clinical and Laboratory Standards Institute (CLSI) methods. Zone diameters and MIC values were interpreted using CLSI breakpoints (CLSI, Performance Standards for Antimicrobial Susceptibility Testing. M100-S27, 2017) for Staphylococcus aureus/Staphylococcus lugdunensis, coagulase-negative staphylococci (CoNS), and Staphylococcus pseudintermedius Results were compared to those of mecA PCR. Twenty-nine of 90 (32%) isolates were mecA positive. Oxacillin inhibition zone sizes and MICs interpreted by S. pseudintermedius breakpoints reliably differentiated mecA-positive and mecA-negative isolates, with a categorical agreement (CA) of 100% and no very major errors (VMEs) or major errors (MEs) for all media. For cefoxitin DD results interpreted using S. aureus/S. lugdunensis and CoNS breakpoints, CA values were 85% and 75%, respectively, and there were 72% and 64% VMEs, respectively, and 0 MEs. For cefoxitin MICs interpreted using S. aureus/S. lugdunensis breakpoints, CA was 81%, and there were 60% VMEs and no MEs. Our data demonstrate that oxacillin DD or MIC testing methods using the current S. pseudintermedius breakpoints reliably identify mecA-mediated oxacillin resistance in S. schleiferi, while cefoxitin DD and MIC testing methods perform poorly.

First Report of Black Leaf Mold of Tomato Caused by Pseudocercospora fuligena in Ohio

Diseased tomato (Solanum lycopersicum L. cvs. Geronimo, Rebelski, and Big Dena) plants were received for diagnosis from a home gardener in Wayne County, Ohio, in August 2013 and from a 0.14-ha greenhouse in Brown County, Ohio, in September 2013. Approximately 10 and 60% of leaf area was diseased in the home garden and greenhouse, respectively. One or more lesions, each with an indistinct border, were observed on the leaves. Black fungal growth was observed on both sides of the leaf in association with the lesions. Microscopic examination revealed Cercospora-like conidia (2). Three symptomatic leaves from each location were surface-sterilized with 0.5% NaClO for 1 min and cultured on V8 juice agar medium at room temperature under continuous fluorescent lighting. One isolate was selected from each of Wayne Co. (SAM33-13) and Brown Co. (SAM34-13). The fungus produced small, dark-brown colonies within 2 weeks of plating. Mycelium was olive brown and septate, producing fascicles of conidiophores. Conidia were cylindrical, 2 to 14 septate, and 25.8 to 109.7 × 6.5 μm. Genomic DNA was extracted from colonies of isolate SAM33-13 grown on V8 juice agar medium using the Wizard SV Genomic DNA Purification System (Promega, Madison, WI). The internal transcribed spacer (ITS) region of rDNA was amplified by PCR using primer pair ITS1 and ITS4 (5), and the purified amplicon was sequenced (OARDC Molecular and Cellular Imaging Center, Wooster, OH). The ITS sequence was 99% identical to those of GenBank accessions of Pseudocercospora fuligena from Korea (JX290079) and Thailand (GU214675). The sequence was deposited in GenBank (KF931141). Based on morphology (4) and sequence analysis, the fungus was identified as P. fuligena (Roldan) Deighton (basionym Cercospora fuligena). To satisfy Koch's postulates, three 4-week-old tomato plants each of the cultivars L390 (AVRDC, Taiwan) and Mountain Spring (Siegers Seed Co., Holland, MI) were sprayed with a suspension of 1 × 10³ conidia/ml of isolates SAM33-13 or SAM34-13 prepared from 3-week-old cultures growing on V8 juice agar medium. Three non-inoculated control plants were sprayed with sterilized water. Plants were maintained in a growth chamber at 25 to 30°C, 80% RH, and a 12 h/12 h day/night cycle. The first symptoms appeared 3 weeks after inoculation as light yellow foliar lesions. The lesions enlarged and turned black due to fungal growth, and the infected leaves dried. Disease severity was 70 and 10% of leaf area for cvs. L390 and Mountain Spring, respectively, for each isolate. Non-inoculated control plants were symptomless, and no fungus was re-isolated from the leaves. P. fuligena was isolated from symptomatic leaves of inoculated plants as described above, and the identity was confirmed based on morphology. In the United States, C. fuligena has not been reported infecting tomato since the first report in Florida in 1974 (1). To our knowledge, this is the first report of black leaf mold of tomato caused by P. fuligena in Ohio. Resistant cultivars, crop sanitation, and fungicides are recommended to manage the disease (3). References: (1) C. H. Blazquez and S. A. Alfieri. Phytopathology 64:443, 1974. (2) U. Braun. IMA Fungus 4:265, 2013. (3) R. Cerkauskas. AVRDC Publication 04-606, 2004. (4) B. Halfeld-Vieira et al. Fitopatol. Bras. 31:3, 2006. (5) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

First Report of Tomato chlorotic spot virus Infecting Tomatoes in Ohio

Virus-like symptoms including deformation, discoloration, and necrotic ringspots on green and red fruits of tomato (Solanum lycopersicum L. cv. Big Dena) were observed in a 400 m² commercial high tunnel in Wayne Co., Ohio, in July and August 2013. No symptoms were observed on leaves. Incidence of symptomatic fruits was approximately 15%. Tomato seedlings transplanted into the high tunnel were produced in a greenhouse containing ornamental plants. The grower observed high levels of thrips infestation in the tomato seedlings prior to transplanting. A tospovirus was suspected as a possible causal agent. Four symptomatic fruits were tested using immunostrip tests for Tomato spotted wilt virus (TSWV) and Impatiens necrotic spot virus (INSV) (Agdia, Inc., Elkhart, IN), a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for Groundnut ringspot virus (GRSV)/Tomato chlorotic spot virus (TCSV) (Agdia, Inc., Elkhart, IN), and DAS-ELISA for TCSV (AC Diagnostics Inc., Fayetteville, AR). All of the symptomatic fruits tested negative with Agdia immunostrips and positive with the Agdia and AC Diagnostics DAS-ELISAs. Total RNA was extracted from one ELISA-positive sample using TRIZOL Reagent (Life Technologies, Carlsbad, CA) and tested in RT-PCR using GRSV- or TCSV-specific primers (2). An expected RT-PCR product was generated using primers derived from TCSV S-RNA (JAP885, 5'-CTCGGTTTTCTGCTTTTC-3' and JAP886, 5'CGGACAGGCTGGAGAAATCG3') (~290 bp) but not when using primers specific to GRSV S-RNA (JAP887, 5'-CGTATCTGAGGATGTTGAGT-3' and JAP888, 5'-GCTAACTCCTTGTTCTTTTG-3'). The 290-bp RT-PCR product was cloned using a TOPO TA cloning kit (Life Technologies, Grand Island, NY), and six clones were sequenced. Sequences from three clones were identical to a consensus sequence of a 292-bp fragment covering part of the TCSV nucleocapsid gene (GenBank Accession No. KJ744213). Sequences of the remaining three clones contained one, two, or three nucleotide mutations. To confirm the presence of TCSV in this sample, two newly designed primers flanking the entire nucleocapsid protein gene (TCSV-F1, 5'-AGTATTATGCATCTATAGATTAGCACA-3' and TCSV-R1, 5'-ACAAATCATCACATTGCCAGGA-') were used in RT-PCR to generate an expected 948-bp product. Upon cloning and sequencing, this fragment was shown to contain a full nucleocapsid protein gene of TCSV (GenBank Accession No. KM610235). The fragment contained a sequence identical to the first 292-bp RT-PCR product. BLASTn analysis (National Center for Biotechnology Information database) showed that the large fragment sequence had 98% nucleotide sequence identity to the TCSV Florida isolate (GenBank Accession No. JX244196) and 94% to the TCSV Physalis isolate (GenBank Accession No. JQ034525). Tobacco plants were inoculated mechanically with sap from symptomatic tomato fruits. Necrotic local lesions developed, and the presence of TCSV was confirmed using AC Diagnostics' DAS-ELISA. TCSV has been reported in Brazil (1), Puerto Rico (3), and Florida (2). To our knowledge, this is the first report of TCSV infecting tomatoes in Ohio. Because TCSV is transmitted by thrips and has a broad host range, this emerging virus could pose a significant threat to the U.S. vegetable industry. References: (1) A. Colariccio et al. Fitopatol. Bras. 20:347, 1995. (2) A. Londoño et al. Trop. Plant Pathol. 37:333, 2012. (3) C. G. Webster et al. Plant Health Progress doi:10.1094/PHP-2013-0812-01-BR, 2013.

Quantification and genotyping of lipoprotein lipase in patients with diabetic lipaemia

AIMS

To determine if diabetic lipaemia is caused by loss of function mutations in the lipoprotein lipase gene, LPL.

METHODS

We conducted a case-control study over 2 years in two tertiary care hospitals in South Australia. Six patients with a history of diabetic lipaemia and 12 control subjects, with previous diabetic ketoacidosis and peak triglyceride concentrations < 2.4 mmol/l were included. Participants were well at the time of study investigations.

RESULTS

Only one patient with lipaemia had a loss of function mutation in LPL and no functional mutations in APOC2 or GPIHBP1 were identified. The mean lipoprotein lipase concentration was lower in patients with diabetic lipaemia than in control subjects (306 vs. 484 μg/l, P = 0.04). The mean fasting C-peptide concentration was higher in patients with diabetic lipaemia than in control subjects (771 vs. 50 pmol/l; P = 0.001).

CONCLUSIONS

Lipoprotein lipase deficiency in patients with a history of diabetic lipaemia was predominantly quantitative, rather than secondary to mutations in LPL, APOC2 or GPIHBP1. The majority of patients with severe hypertriglyceridaemia in diabetic ketoacidosis may have ketosis-prone Type 2, rather than Type 1, diabetes.

First Report of Anthracnose of Onion Caused by Colletotrichum coccodes in Ohio

Dry bulb onion (Allium cepa L. cvs. Pulsar, Bradley, and Livingston) plants with symptoms of anthracnose were observed in three commercial fields totaling 76.5 ha in Huron Co., Ohio, in July 2013. Symptoms were oval leaf lesions and yellowing, curling, twisting, chlorosis, and death of leaves. Nearly half of the plants in a 32.8-ha field of the cv. Pulsar were symptomatic. Concentric rings of acervuli with salmon-colored conidial masses were observed in the lesions. Conidia were straight with tapered ends and 16 to 23 × 3 to 6 μm (2). Colletotrichum coccodes (Wallr.) S. Hughes was regularly isolated from infected plants (2). Culturing diseased leaf tissue on potato dextrose agar (PDA) amended with 30 ppm rifampicin and 100 ppm ampicillin at room temperature yielded white aerial mycelia and salmon-colored conidial masses in acervuli. Numerous spherical, black microsclerotia were produced on the surface of colonies after 10 to 14 days. To confirm pathogen identity, total DNA was extracted directly from a 7-day-old culture of isolate SAM30-13 grown on PDA, using the Wizard SV Genomic DNA Purification System (Promega, Madison, WI) following the manufacturer's instructions. The ribosomal DNA internal transcribed spacer (ITS) region was amplified by PCR using the primer pair ITS1 and ITS4 (2), and sequenced. The sequence, deposited in GenBank (KF894404), was 99% identical to that of a C. coccodes isolate from Michigan (JQ682644) (1). Ten onion seedlings cv. Ebenezer White at the two- to three-leaf stage of growth were spray-inoculated with a conidial suspension (1 × 10⁵ conidia/ml containing 0.01% Tween 20, with 10 ml applied/plant). Plants were maintained in a greenhouse (21 to 23°C) until symptoms appeared. Control plants were sprayed with sterilized water containing 0.01% Tween 20, and maintained in the same environment. After 30 days, sunken, oval lesions each with a salmon-colored center developed on the inoculated plants, and microscopic examination revealed the same pathogen morphology as the original isolates. C. coccodes was re-isolated consistently from leaf lesions. All non-inoculated control plants remained disease-free, and C. coccodes was not re-isolated from leaves of control plants. C. coccodes was reported infecting onions in the United States for the first time in Michigan in 2012 (1). This is the first report of anthracnose of onion caused by C. coccodes in Ohio. Unusually wet, warm conditions in Ohio in 2013 likely contributed to the outbreak of this disease. Timely fungicide applications will be necessary to manage this disease in affected areas. References: (1) A. K. Lees and A. J. Hilton. Plant Pathol. 52:3. 2003. (2) L. M. Rodriguez-Salamanca et al. Plant Dis. 96:769. 2012. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

First Report of Bloat Nematode (Ditylenchus dipsaci) Infecting Garlic in Ohio

Bloat nematode, Ditylenchus dipsaci (Kühn) Filipjev (also known as stem and bulb nematode), is a key pest of garlic (Allium sativum) globally (1) as heavy infestations can lead to complete crop loss. Although not a major crop in Ohio, garlic is grown in diversified vegetable production systems. In July 2013, diseased garlic bulbs were received from a grower in Lorain County, OH, from a field with wide symptom distribution. Bulbs were discolored, exhibited splitting, and had basal plate damage including reduced roots. Nematodes were extracted for examination by placing bulb slices in water. Recovered nematodes had morphological characteristics of D. dipsaci, including a short stylet with prominent knobs, a distinct median esophageal bulb, a basal bulb slightly overlapping the intestine, a conical and pointed tail, and males with distinct bursa (1). To confirm the identity of the nematode, further morphological and molecular studies were performed. Nematode images were captured on a DM IRB inverted microscope (Leica Microsystems, Wetzlar, Germany) using a Retiga 2000 camera (Q Imaging, Surrey, Canada). Images were analyzed using Image J (NIH). For females (n = 16), means and ranges were: L = 1,080.1 (972.2 to 1,229.5) μm, a = 36.6 (33.5 to 41.9), b = 6.2 (5.3 to 6.8), c = 11.1 (9.1 to 12.8), and stylet 10.1 (8.9 to 11.2) μm. For males (n = 6), L = 1,589.2 (1,494 to 1,702.7) μm, a = 43.0 (40.7 to 46.0), b = 6.9 (6.4 to 7.3), c = 11.7 (9.2 to 13), with stylet 10.8 (10 to 12.2) μm and spicules 25.2 (23.8 to 26.8) μm. The measurements were highly similar to those of D. dipsaci (1). DNA was extracted from 50 to 100 nematodes using a PowerSoil DNA Isolation Kit (Mo-Bio Laboratories, Inc., Carlsbad, CA) as well as from individual females, and partial ITS sequences were amplified using primer set TW81/AB28 (3). The partial ITS sequences shared 99 to 100% sequence identity with GenBank accessions of D. dipsaci from garlic (DQ452956, JX123258). Expansion segments D2-D3 were sequenced following amplification of DNA from individual females using primer set D2A/D3B (4) and shared 99% sequence identity with D. dipsaci from garlic (FJ707362, JX123259). In this case, the grower noted bloat nematode symptoms following the introduction of new planting material into the field. Therefore, the availability of bloat nematode-free planting material or treated bulbs (2) is essential for preventing introduction of this pathogen. Once established, management options are limited as this nematode is difficult to eliminate. With this first report of D. dipsaci on garlic in Ohio, we have identified a new pest that can greatly reduce garlic yields in this state. References: (1) W. Nickle, ed. Ditylenchus. In: Manual of Agricultural Nematology, 1991. (2) P. Roberts et al. J. Nematol. 27:448, 1995. (3) S. Subbotin et al. Phytopathology 95:1308, 2005. (4) G. Tenente et al. Nematropica 34:1, 2004.

First Report of Bacterial Wilt Caused by Ralstonia solanacearum in Ghana, West Africa

Tomato and pepper plants exhibiting wilt symptoms were collected from fields in seven villages in Northern (Vea, Tono, Pwalugu), Ashanti (Agogo, Akumadan), and Brong Ahafo (Tanoso, Tuobodom) regions of western Ghana in November 2012. The plants were wilted without leaf yellowing or necrosis. Disease incidence was generally low, with less than 20% symptomatic plants observed. Most of the plants collected produced visible bacterial ooze in water in the field. Ooze was plated on 2,3,5-triphenyltetrazolium chloride-amended (TZC) medium. Isolated colonies were fluidal, irregularly round, white with pink centers, gram-negative, and oxidase positive. One strain from each of seven fields was selected for further study. All strains induced a hypersensitive reaction on tobacco. Randomly selected strains SM855-12 and SM857-12 tested positive in R. solanacearum ImmunoStrip assays (Agdia Inc., IN). An end-point PCR assay with primer set 759/760 (3) generated an R. solanacearum-specific 280-bp amplicon for all seven strains. Two of these strains were biovar I and the remaining five were biovar III based on utilization of cellobiose, lactose, maltose, dulcitol, mannitol, and sorbitol. A phylotype-specific multiplex PCR assay that recognizes four geographically linked monophyletic groups within R. solanacearum (1) indicated that one strain (SM855-12) was phylotype III (African origin), whereas the other six were phylotype I (Asian origin). All strains were subjected to repetitive sequence-based PCR (Rep-PCR) with BOXA1R and REP1R/REP2 primers (4). Strain SM855-12 was grouped with the phylotype III reference strain UW 368 and the remaining six strains were grouped with the phylotype I reference strain GMI 1000. A pathogenicity test was performed with bacterial wilt-susceptible tomato line OH7814. Inoculum was prepared from 48-h cultures of strains SM855-12, SM856-12, and SM858-12 grown on casamino acid peptone glucose (CPG) medium at 30°C. Roots of ten 4-week-old tomato plants per strain were drench-inoculated with 5 ml of a 10⁸ CFU/ml bacterial suspension after wounding with a sterile scalpel. Non-inoculated control plants were drenched with 5 ml distilled water after root wounding. Plants were kept in a greenhouse at 25 to 30°C. By 12 days after inoculation, 80 to 100% of inoculated plants were wilted, whereas no symptoms appeared in non-inoculated plants. Bacteria re-isolated from wilted plants were confirmed to be R. solanacearum using techniques mentioned above. Although an association of bacterial wilt with tomato/pepper was mentioned previously (2), to our knowledge, this is the first documented report of bacterial wilt caused by R. solanacearum in Ghana. The presence of Asian strains (phylotype I) may be the result of one or more accidental introductions. Awareness of this disease in Ghana will lead to deployment of management strategies including use of resistant varieties and grafting desirable varieties onto disease-resistant rootstocks. References: (1) M. Fegan and P. Prior. Page 449 in Bacterial Wilt Disease and the Ralstonia solanacearum Species Complex. C. Allen et al., eds. American Phytopathological Society, St. Paul, MN, 2005. (2) K. A. Oduro. Plant Protection and Regulatory Services Directorate of MOFA, Accra, Ghana, 2000. (3) N. Opina et al. Asia Pac. J. Mol. Biol. Biotechnol. 5:19, 1977. (4) J. Versalovic et al. Methods Mol. Cell Biol. 5:25, 1994.

Photoassociation of long-range nD Rydberg molecules

We observe long-range homonuclear diatomic nD Rydberg molecules photoassociated out of an ultracold gas of Rb87 atoms for 34≤n≤40. The measured ground-state binding energies of Rb87(nD+5S1/2) molecular states are larger than those of their Rb87(nS+5S1/2) counterparts, which shows the dependence of the molecular bond on the angular momentum of the Rydberg atom. We exhibit the transition of Rb87(nD+5S1/2) molecules from a molecular-binding-dominant regime at low n to a fine-structure-dominant regime at high n [akin to Hund's cases (a) and (c), respectively]. In the analysis, the fine structure of the nD Rydberg atom and the hyperfine structure of the 5S1/2 atom are included.

First Report of Leek yellow stripe virus in Garlic in Ohio

Leek yellow stripe virus (LYSV), genus Potyvirus, family Potyviridae, infects a wide range of Allium species worldwide. LYSV is one of several viruses that chronically infect garlic, Allium sativum L. The garlic virus complex, which includes LYSV, Onion yellow dwarf virus, and Garlic common latent virus, is perpetuated by asexual propagation (4) and is transmitted to clean planting material by aphids (3). This virus complex can reduce garlic bulb weight by nearly three quarters (2), and LYSV-only infections can result in approximately a one-quarter reduction in bulb weight (2). Garlic is grown as a small-scale, specialty crop in Ohio. During late May and early June 2013, garlic plants with virus-like symptoms were collected from Medina, Holmes, and Wayne counties, Ohio. Plants exhibited chlorotic streaking, foliar dieback, dwarfing, small bulbs, and cylindrical bulbs that failed to differentiate into cloves. Incidence of affected plants in the fields was up to 5% and all fields had early season aphid infestations. Flexuous rods were observed in TEM micrographs of plant sap from symptomatic leaves. Five symptomatic plants and six asymptomatic plants (from fields with symptomatic plants) were evaluated for LYSV by DAS-ELISA (Agdia, Inc., Elkhart, IN). Reverse transcriptase (RT)-PCR with LYSV-specific primers LYSV-WA and LYSV-WAR (3) was performed with cDNA generated by the High Capacity cDNA Reverse Transcription Kit (Applied Biosystems, Foster City, CA). Both foliar and bulb tissues were tested using both detection methods. Forty percent of symptomatic plants and 67% of asymptomatic plants tested positive for LYSV with both ELISA and RT-PCR. LYSV was detected in both foliar and bulb tissues, including both tissues from asymptomatic plants. Five PCR amplicons generated from both foliar and bulb tissue were sequenced and shown to share 96 to 98% maximum identity with an LYSV polyprotein gene accession in GenBank (AY842136). This provided additional support that the detected virus was LYSV. LYSV was initially difficult to detect in Ohio fields due to low disease incidence and subtle symptom development. Use of virus-tested garlic bulbs can improve yield for several years, even following viral reinfection by aphids, compared to growing garlic from chronically infected bulbs (1). However, many growers routinely save bulbs from year to year and lack access to or knowledge of virus-tested sources of garlic bulbs. Conducive conditions, chronic infections, or co-infections with other viruses enhance the severity of symptoms and yield loss (2). LYSV has previously been reported in garlic producing regions of the northwestern United States (3), and to our knowledge, this is the first report of LYSV in garlic in Ohio. References: (1) V. Conci et al. Plant Dis. 87:1411, 2003. (2) P. Lunello et al. Plant Dis. 91:153, 2008. (3) H. Pappu et al. Plant Health Progress 10, 2008. (4) L. Parrano et al. Phytopathol. Mediterr. 51:549, 2012.

Assessing the efficacy of pre-harvest, chlorine-based sanitizers against human pathogen indicator microorganisms and Phytophthora capsici in non-recycled surface irrigation water

Many factors must be considered in order to develop and implement treatment systems to improve the microbial quality of surface water and prevent the accidental introduction of plant and human pathogens into vegetable crops. The efficacy of chlorine gas (Cl2(g)) and chlorine dioxide (ClO2) injection systems in combination with rapid sand filtration (RSF) was evaluated in killing fecal indicator microorganisms in irrigation water in a vegetable-intensive production area. The efficacy of ClO2 and Cl2(g) was variable throughout the distribution systems and coliform bacteria never dropped below levels required by the United States Environmental Protection Agency for recreational waters. Sampling date and sampling point had a significant effect on the abundance of coliforms in Cl2(g)- and ClO2-treated water. Sampling date and sampling point also had a significant effect on the abundance of generic Escherichia coli in Cl2(g) treated water but only sampling point was significant in ClO2 treated water. Although the waterborne plant pathogen Phytophthora capsici was detected in five different sources of surface irrigation water using baiting and P. capsici-specific PCR, in vitro studies indicated that ClO2 at concentrations similar to those used to treat irrigation water did not reduce mycelial growth or direct germination of P. capsici sporangia and reduced zoospore populations by less than 50%. This study concludes that injection of ClO2 and Cl2(g) into surface water prior to rapid sand filtration is inadequate in reducing fecal indicator microorganism populations and ClO2 ineffectively kills infectious propagules of P. capsici. Additional research is needed to design a system that effectively targets and significantly reduces both plant and human pathogens that are present in surface irrigation water. A model for a multiple barrier approach to treating surface water for irrigation is proposed.

First Report of Bacterial Leaf Spot of Parsley Caused by Pseudomonas syringae pv. coriandricola in Ohio

A severe leaf spot of parsley (Petroselinum crispum L. cvs. Dark Green Italian and Gigante) was observed on ∼1.5 ha in 2007 and 8 ha in 2012 on three vegetable farms in northern Ohio. Tiny, water-soaked spots that enlarged to necrotic lesions (∼5 mm wide) were first observed in June of each year. Lesions often coalesced and leaf marginal necrosis was common. Disease incidence initially ranged from 20 to 50%, and a 1.5-ha field was completely lost in 2012 as a result of the disease. Bacterial streaming was observed microscopically from leaf lesions. Diseased leaf tissue was dipped briefly in 70% ethanol, rinsed in sterile water, and blotted dry. Bacteria were isolated by plating 10-fold serial dilutions of diseased tissue extracts onto yeast dextrose carbonate and Pseudomonas F (PF) agar media. Whitish, opaque, circular colonies were isolated consistently from all samples. One isolate was purified from each of four fields. They were all gram-negative, non-fluorescent on PF medium, levan positive, oxidase negative, arginine dihydrolase negative, potato rot negative, and tobacco hypersensitive reaction positive. Repetitive extragenic palindromic sequence (Rep)-PCR fingerprint profiles using the BOXA1R primer (4) were identical for the four isolates. A pathogenicity test was conducted with strain SM69-07 isolated in 2007. A bacterial culture was suspended in sterile potassium phosphate buffer (0.01M, pH 7.4) and adjusted to 10⁸ CFU/ml. Four 4-week-old plants each of parsley and cilantro (Ferry-Morse Seed Co.) were inoculated by spraying the bacterial suspension on the leaves until runoff. Potassium phosphate buffer was applied as a negative control treatment for each plant species. Plants were kept in a mist room with 100% humidity for 4 h, then transferred to a greenhouse with average maximum and minimum temperatures of 30 and 25°C. Leaf symptoms similar to those on the original plants were observed on the inoculated parsley and cilantro plants within 14 days of inoculation, whereas no symptoms developed on the negative control plants. One bacterial isolate obtained from each inoculated host using the isolation method described above was confirmed to be identical to the original isolates using the LOPAT tests and Rep-PCR DNA fingerprint profiles; no target bacteria were isolated from the negative control plants. Multilocus sequence typing (MLST) of the housekeeping genes gap1, gltA, gyrB, and rpoD was conducted for strain Sm69-07 (2,3). Sequence data were subjected to BLASTn searches in the Plant-Associated Microbes Database (PAMDB, http://genome.ppws.vt.edu/cgi-bin/MLST/home.pl ) (1). The sequences aligned with those of Pseudomonas syringae pv. coriandricola with 100% identity to alleles 101 (gyrB), 123 (rpoD), 7 (gap1), and 64 (gltA). Strain information and sequence alignment results for SM69-07 were submitted to PAMDB and assigned as isolate ID 1138. Based on bacterial culture morphology, LOPAT profile, pathogenicity test results, and MLST, the pathogen was confirmed as P. syringae pv. coriandricola. To our knowledge, this is the first report of bacterial spot of parsley caused by P. syringae pv. coriandricola in Ohio. Due to stringent quality requirements for fresh market parsley, this disease may pose a threat to the economic sustainability of parsley production in Ohio. References: (1) N. F. Almeida et al. Phytopathology 100:208, 2010. (2) C. T. Bull et al. Phytopathology 101:847, 2011. (3) M. S. Hwang et al. Appl. Environ. Microbiol. 71:5182, 2002. (4) J. Versalovic et al. Methods Mol. Cell Biol. 5:25, 1994.

First Report of Tomato Pith Necrosis Caused by Pseudomonas mediterranea in the United States and P. corrugata in Ohio

Tomato (Solanum lycopersicum, cvs. Mountain Fresh, Big Dena, and Trust) plants with symptoms of pith necrosis were received from six commercial high tunnels in Ohio during May and July 2012. Disease incidence ranged from 1 to 5%. Symptoms included wilting of shoots, dry, dark brown coalescent lesions on stems, brown discolored pith with a ladder-like appearance, and in some cases, adventitious root formation. Bacterial streaming was observed microscopically from necrotic stem tissue. Bacteria were isolated from surface-sterilized diseased stem tissue by plating 10-fold serial dilutions onto yeast dextrose carbonate (YDC) and Pseudomonas F (PF) agar media. The majority of the colonies recovered were similar in morphology on YDC: round and mucoid, with a greenish center that later became dry and winkled with a curly margin, and producing a yellow-green diffusible pigment. Colonies were creamy, yellow-brown in color and non-florescent on PF medium. Nine isolates from six plant samples were purified. All isolates were gram-negative, levan negative, oxidase positive, and potato rot negative. Three isolates were positive and six were negative for arginine dihydrolase activity. None induced a hypersensitive reaction in tobacco. All isolates grew at 37°C. The isolates were further identified by PCR assays using species-specific primers PC5/1-PC5/2 for Pseudomonas corrugata and PC1/1-PC1/2 for P. mediterranea (1,2). DNA of a reference P. mediterranea strain from Turkey was used as a positive control. A 600-bp band was amplified using P. mediterranea primers from the six arginine dihydrolase negative isolates recovered from four of six samples. An 1,100-bp band was amplified from the three arginine dihydrolase positive isolates from two other samples using P. corrugata primers. The 600-bp PCR products amplified from the P. mediterranea reference strain and isolate SM664-12 were purified and sequenced. The DNA sequence of SM664-12 was 99% aligned with that of the reference strain from Turkey and a BLAST search in NCBI indicated only one match with P. mediterranea strain G-229-21 (Accession No. EU117098.1), with an E-value 1e-145 and 84% identity. P. mediterranea (SM664-12) and P. corrugata (SM658-12) were each inoculated onto four 4-week-old tomato plants (cv. Mountain Fresh) by injecting a 50 μl bacterial suspension (10⁸ CFU/ml) into the stem at the axil of the first true leaf (2). Negative control plants were injected with sterile water. Plants were kept in a mist chamber for 72 h at 25°C, then moved into a growth chamber maintained at 25/20°C day/night, 12-h light/dark, and 80% relative humidity. Plants exhibited dark brown lesions at the inoculation site after 4 weeks and brown discoloration of the pith developed, whereas no lesions were observed in control plants. The reisolated bacteria were tested by PCR and identified as P. corrugata and P. mediterranea. Therefore, we have confirmed that tomato pith necrosis in Ohio involves at least two bacteria, P. corrugata and P. mediterranea. Although tomato pith necrosis has been observed in Ohio since the 1990s, to our knowledge, this is the first confirmation of a causal agent as P. corrugata in Ohio and the first report of P. mediterranea causing tomato pith necrosis in the United States. References: (1) V. Catara et al. Eur. J. Plant Pathol. 106:753, 2000. (2) V. Catara et al. Int. J. Syst. Evol. Microbiol. 52:1749, 2002.

Suicide, guns, and public policy

Suicide is a serious public health concern that is responsible for almost 1 million deaths each year worldwide. It is commonly an impulsive act by a vulnerable individual. The impulsivity of suicide provides opportunities to reduce the risk of suicide by restricting access to lethal means. In the United States, firearms, particularly handguns, are the most common means of suicide. Despite strong empirical evidence that restriction of access to firearms reduces suicides, access to firearms in the United States is generally subject to few restrictions. Implementation and evaluation of measures such as waiting periods and permit requirements that restrict access to handguns should be a top priority for reducing deaths from impulsive suicide in the United States.

First Report of Impatiens Downy Mildew Caused by Plasmopara obducens in Ohio

Single and double flowered impatiens (Impatiens walleriana Hook.f.) plants with symptoms of downy mildew were found in commercial greenhouses in Delaware, Wayne, and Holmes counties, Ohio, in April 2012. Plants were stunted and defoliated. Symptoms on remaining leaves included general chlorosis without discrete spots and downward curling of leaves. A downy white growth was observed on the lower surface of infected leaves. The disease was widespread in affected greenhouses and incidence in cvs. Shimmer Coral, Accent Mix, and Super Elfin was nearly 90%. The downy growth consisted of coenocytic mycelia, monopodial sporangiophores, and ovoid, hyaline sporangia typical of Plasmopara obducens (J. Schröt.) J. Schröt in Cohn (1,2,4). Sporangia were borne on branchlets measuring 5 to 15 μm long (average 10 μm) at right angles to the main axis of the sporangiophore. Sporangia were 9.4 to 17.5 × 12.8 to 16.3 μm. No oospores were observed. Total DNA was extracted directly from plant tissue with the Wizard SV Genomic DNA Purification System (Promega, Madison, WI) following the manufacturer's instructions. Large ribosomal subunit DNA was amplified by PCR using primers NL-1 and NL-4 (3). Amplicons of 690 bp and 834 bp were produced from each diseased sample, while only the 690-bp amplicon was produced from healthy tissue. DNA from each amplicon of sample IDM041712 was purified using the Wizard SV Gel and PCR Clean-Up System (Promega), sequenced, and the sequence of the diagnostic 834-bp amplicon was deposited in GenBank (JX142134). The sequence of the 834-bp amplicon was 99% similar to those of P. obducens isolates from Serbia (HQ246451) (1), the UK (AY587558), and Austria (EF196869). The sequence of the 690-bp amplicon (JX142135) was 99% similar to that of I. walleriana (HQ223336). Twelve young impatiens 'Shimmer Coral' plants were inoculated with sporangia washed from infected leaves (1 × 10⁴ sporangia/ml). Plants were incubated at room temperature for 24 h in a moist chamber and then maintained in a greenhouse (21 to 23°C) until symptoms appeared. Control plants were sprayed with sterile water and maintained in the same environment. After 12 to 14 days, typical symptoms of downy mildew developed on the inoculated plants and microscopic examination revealed the same pathogen morphology as the original isolate. All non-inoculated control plants remained disease free. To our knowledge, this is the first report of downy mildew on impatiens in Ohio. This disease caused considerable economic losses in Ohio in 2012 and is likely to be a recurring problem requiring intensive preventative management. References: (1) A. Bulajic et al. Plant Dis. 95:491, 2011. (2) O. Constantinescu. Mycologia 83:473, 1991. (3) W. Maier et al. Can. J. Bot. 81:12, 2003. (4) S. N. Wegulo et al. Plant Dis. 88:909, 2004.

First Report of Xanthomonas gardneri Causing Bacterial Spot of Tomato in Ohio and Michigan

In 2009 and 2010, outbreaks of bacterial spot characterized by significant fruit spotting occurred in at least 2,000 ha of commercial processing tomatoes in northwest Ohio and southeast Michigan. Losses were estimated at $7.8 million. Diseased fruit and foliage were collected from 32 Ohio and Michigan fields in 2010. Excised lesions from fruit and leaves were dipped briefly in 70% ethanol, air dried, and chopped into pieces in 10 mM potassium phosphate buffer (KPB), pH 7.4. Ten-fold serial dilutions in KPB were plated on yeast dextrose carbonate agar medium and 83 yellow mucoid colonies were purified. All isolates were gram negative and induced a hypersensitive response in tobacco (Nicotiana tabacum) plants 24 h after inoculation with a 10⁸ CFU/ml bacterial suspension in water. All 83 isolates were identified as Xanthomonas spp. using genus-specific primers RST65/69 (2). Of these, 11 were identified as X. euvesicatoria and 8 as X. perforans using the species-specific primers RST27/28 (1) and JJ19/22 (5'-AACCCAACTAATTTCCCTC-3' and 5'-AACGAGATTTGTTACGAACC-3'; J. B. Jones, personal communication), respectively. DNA fingerprint profiles of 62 of the 64 remaining strains generated using BOX-PCR assays (4) were identical to the profile of X. gardneri type strain XCGA2. The DNA profiles of 2 of the 64 Xanthomonas strains did not resemble those of any reference strains. The 16S rDNA and ITS1 genes from two representative strains (SM174-10 and SM230-10) were PCR amplified, direct sequenced, and aligned using nBLAST with the same gene region from XCGA2 (GenBank Accession No. AF123093). Strains SM174-10 and SM230-10 differed from XCGA2 by 2 bp (99% nucleotide similarity). Pathogenicity tests were performed twice on 6-week-old tomato seedlings (cv. Peto 696). Three tomato seedlings were sprayed until runoff with strain SM174-10 (~10⁸ CFU/ml), three seedlings were sprayed similarly with water (control treatment), and all six plants were grown under high relative humidity (24 s of mist per 12 min) at day/night temperatures of 29/23°C for 15 days. Seedlings inoculated with SM174-10 exhibited water-soaked lesions and chlorosis on the foliage, similar to field symptoms, within 14 days. Seedlings sprayed with water did not develop symptoms. Isolates cultured as described above from all three pathogen-inoculated seedlings were similar in morphology to strain SM174-10; no cultures were recovered from water-inoculated plants. The BOX-PCR fingerprint profile of a representative reisolated colony was identical to that of SM174-10. Although bacterial spot of tomato is a common disease in Ohio and Michigan, to our knowledge this is the first report of X. gardneri infecting tomatoes in these states and provides evidence that there may have been a shift in the primary causal agent of bacterial spot from X. euvesicatoria (3) to X. gardneri. References: (1) H. Bouzar et al. Phytopathology 84:39, 1994. (2) A. Obradovic et al. Eur. J. Plant Pathol. 11:285, 2004. (3) F. Sahin. Ph.D. Diss. The Ohio State University, Columbus, 1997. (4) D. J. Versalovic et al. Methods Mol. Cell. Biol. 5:25, 1994.

First Report of 'Candidatus Liberibacter solanacearum' Naturally Infecting Tomatoes in the State of Mexico, Mexico

In January 2011, tomato (Solanum lycopersicum) plants exhibiting stunting, yellow mosaic, short, chlorotic leaves, aborted flowers, and reduced-size fruits, symptoms similar to those exhibited by plants infected by 'Candidatus Liberibacter solanacearum' (2), were observed in approximately 5% of tomato plants in greenhouses in Jocotitlan in the State of Mexico, Mexico. Occasional plant recovery was also observed. Tomato plants in this facility were previously shown to be infected by Mexican papita viroid (MPVd), Pepino mosaic virus (PepMV), and aster yellows phytoplasma. Eight symptomatic leaf samples (designated MX11-01 to MX11-08) were collected and screened against selected tomato viruses and pospiviroids by reverse transcription (RT)-PCR using purified plant RNA or for 'Ca. L. solanacearum' by PCR using purified plant DNA. As expected, both PepMV and MPVd were detected in these samples. However, two 'Ca. L. solanacearum'-specific PCR products (1,168 and 669 bp) were also amplified in two samples (MX11-02 and MX11-05) using primers OA2 (2) and OI2c (1) or CL514F/CL514R (3), respectively. Each 'Ca. L. solanacearum'-specific PCR product was gel purified with Geneclean (Q-Biogene, Carlsbad, CA) and cloned into pCR2.1 using TOPO TA cloning kit (Invitrogen, Carlsbad, CA) and sequenced (Functional Biosciences, Madison, WI). Sequences of 16S rRNA (1,168 bp) in both isolates (GenBank Accession Nos. JF811596 and JF811597) were identical. However, the 669-bp 50S rRNA sequences in these two isolates (GenBank Accession Nos. JF811598 and JF811599) contained two single nucleotide polymorphism (SNP) mutations. BLASTn searches showed that both 16S rRNA and 50S gene sequences in MX11-05 were identical to the 'Ca. L. solanacearum' previously identified on potato in Chihuahua (GenBank Accession Nos. FJ829811 and FJ829812) and Saltillo (GenBank Accession Nos. FJ498806 or FJ498807) in eastern Mexico. These 'Ca. L. solanacearum' isolates were recently classified as the "b" haplotype (4). Alignment analysis of the 'Ca. L. solanacearum' 16S rRNA sequences also revealed the conserved SNP mutations (g.212T > G and g.581T > C) in MX11-02 and MX11-05 as previously identified for other "b" haplotype isolates (4). 'Ca. L. solanacearum' was first identified in greenhouse tomatoes in 2008 in New Zealand (2). It has also been identified in greenhouse and field tomatoes in the United States. 'Ca. L. solanacearum' was previously reported to infect field tomatoes in Sinaloa, Mexico (3), which was recently considered as the "a" haplotype (4). To our knowledge, this is the first report of 'Ca. L. solanacearum' naturally infecting tomatoes in Jocotitlan in the State of Mexico, Mexico. The greenhouse tomato 'Ca. L. solanacearum' may be transmitted from infected solanaceous plants by potato psyllids (Bactericera cockerelli), which were observed in this facility. References: (1) S. Jagoueix et al. Int. J. Syst. Bacteriol. 44:379, 1994. (2) L. W. Liefting et al. Plant Dis. 93:208, 2009. (3) J. E. Munyaneza et al. Plant Dis. 93:1076, 2009 (4) W. R. Nelson et al. Eur. J. Plant Pathol. 130:5, 2011.

Molecular mechanisms by which T-bet regulates T-helper cell commitment

Current research suggests that a number of newly identified T-helper cell subsets retain a degree of context-dependent plasticity in their signature cytokine expression patterns. To understand this process, a major challenge is to determine the molecular mechanisms by which lineage-defining transcription factors regulate gene expression profiles in T-helper cells. This mechanistic information will aid in our interpretation of whether a T-helper cell state that expresses or retains the capacity to re-express a combination of lineage-defining transcription factors will have a stable or more flexible gene expression profile. Studies examining the developmental T-box transcription factor T-bet demonstrate the powerful information that is gained from combining in vivo analysis with basic biochemical and molecular mechanism approaches. Significantly, T-bet's ability to physically recruit epigenetic modifying complexes, in particular a Jmjd3 H3K27-demethylase and a Set7/9 H3K4-methyltransferase complex, to its target genes allows T-bet to effectively reverse and establish new epigenetic states. This observation suggests that until T-bet is permanently extinguished, T-helper cells will retain some plasticity toward a T-helper 1-like program. Therefore, insight into the complexity of T-helper cell commitment decisions will be aided by determining the molecular mechanisms for lineage-defining transcription factors.

Jmjd3 and UTX play a demethylase-independent role in chromatin remodeling to regulate T-box family member-dependent gene expression

The stable and heritable H3K27-methyl mark suppresses transcription of lineage-specific genes in progenitor cells. During developmental transitions, histone demethylases are required to dramatically alter epigenetic and gene expression states to create new cell-specific profiles. It is unclear why demethylase proteins that antagonize polycomb-mediated repression continue to be expressed in terminally differentiated cells where further changes in H3K27 methylation could be deleterious. In this study, we show that the H3K27 demethylases, Jmjd3 and UTX, mediate a functional interaction between the lineage-defining T-box transcription factor family and a Brg1-containing SWI/SNF remodeling complex. Importantly, Jmjd3 is required for the coprecipitation of Brg1 with the T-box factor, T-bet, and this interaction is necessary for Ifng remodeling in differentiated Th1 cells. Thus, Jmjd3 has a required role in general chromatin remodeling that is independent from its H3K27 demethylase potential. This function for H3K27 demethylase proteins may explain their presence in differentiated cells where the epigenetic profile is already established.

CCCTC-binding factor and the transcription factor T-bet orchestrate T helper 1 cell-specific structure and function at the interferon-gamma locus

How cell type-specific differences in chromatin conformation are achieved and their contribution to gene expression are incompletely understood. Here we identify a cryptic upstream orchestrator of interferon-gamma (IFNG) transcription, which is embedded within the human IL26 gene, compromised of a single CCCTC-binding factor (CTCF) binding site and retained in all mammals, even surviving near-complete evolutionary deletion of the equivalent gene encoding IL-26 in rodents. CTCF and cohesins occupy this element in vivo in a cell type-nonspecific manner. This element is juxtaposed to two other sites located within the first intron and downstream of Ifng, where CTCF, cohesins, and the transcription factor T-bet bind in a T helper 1 (Th1) cell-specific manner. These interactions, close proximity of other elements within the locus to each other and to the gene encoding interferon-gamma, and robust murine Ifng expression are dependent on CTCF and T-bet. The results demonstrate that cooperation between architectural (CTCF) and transcriptional enhancing (T-bet) factors and the elements to which they bind is required for proper Th1 cell-specific expression of Ifng.

T-bet-dependent S1P5 expression in NK cells promotes egress from lymph nodes and bone marrow

During a screen for ethylnitrosourea-induced mutations in mice affecting blood natural killer (NK) cells, we identified a strain, designated Duane, in which NK cells were reduced in blood and spleen but increased in lymph nodes (LNs) and bone marrow (BM). The accumulation of NK cells in LNs reflected a decreased ability to exit into lymph. This strain carries a point mutation within Tbx21 (T-bet), which generates a defective protein. Duane NK cells have a 30-fold deficiency in sphingosine-1-phosphate receptor 5 (S1P₅) transcript levels, and S1P₅-deficient mice exhibit an egress defect similar to Duane. Chromatin immunoprecipitation confirms binding of T-bet to the S1pr5 locus. S1P-deficient mice exhibit a more severe NK cell egress block, and the FTY720-sensitive S1P₁ also plays a role in NK cell egress from LNs. S1P₅ is not inhibited by CD69, a property that may facilitate trafficking of activated NK cells to effector sites. Finally, the accumulation of NK cells within BM of S1P-deficient mice was associated with reduced numbers in BM sinusoids, suggesting a role for S1P in BM egress. In summary, these findings identify S1P₅ as a T-bet–induced gene that is required for NK cell egress from LNs and BM.

An essential interaction between T-box proteins and histone-modifying enzymes

Cellular differentiation requires precisely coordinated events to induce developmentally appropriate gene expression profiles. Lineage-defining transcription factors are responsible for establishing cell-type specific gene expression patterns during development. Recently, we reported a novel mechanism by which the T-box transcription factor T-bet interacts with JMJD3, an H3K27-demethylase, and Set7/9, an H3K4-methyltransferase (Genes Dev. 2008. 22: 2980-2993). Importantly, separable contact points in the T-box DNA binding domain mediate these interactions. Due to the highly conserved nature of the contact residues, these represent common interactions for the T-box family. Therefore, studies examining the molecular mechanisms that account for the ability of T-bet to regulate Ifng and Cxcr3, prototypic CD4+ Th1 genes, have provided novel insight into essential regulatory events that occur at diverse developmental transitions. In this article, we discuss the implications for these findings as well as explore the role epigenetic mechanisms may play in the development of human genetic diseases that are caused by T-box mutations, including congenital heart defects, cleft palate, pituitary deficiencies, and Ulnar-mammary syndrome.

First Report of Bacterial Wilt of Tomato (Solanum lycopersicum) Caused by Ralstonia solanacearum in Benin

In June 2004, wilted tomatoes with no foliar yellowing were observed in Ouègbo, Atlantique District, Benin. The cut tomato stems released whitish bacterial ooze. Longitudinal sections of most stems showed brown vascular discoloration. Twenty symptomatic tomato plants were collected from 10 fields and exported to the Institute of Plant Disease and Plant Protection, Leibniz Universität Hannover, Germany. Bacteria were isolated on triphenyl tetrazolium chloride (TTC) medium (2) and three of the nine bacterial isolates that resembled Ralstonia solanacearum (colonies with red center and whitish periphery) and reference strain ToUdk (race 1 biovar 3; N. Thaveechai, Kasetsart University, Bangkok, Thailand) were used for pathogenicity tests. Five 4-week-old tomato plants cv. Tohounvi, grown in individual plastic pots (14 × 16 cm) containing sterilized field soil, were inoculated with each of the four isolates individually by soil drenching with 30 ml of the test cultures at 10⁸ CFU/ml. Control plants were treated with 30 ml of sterile water. All plants were incubated in a glasshouse at 30°C. All plants inoculated with the isolates from Benin wilted 4 days after inoculation with symptoms similar to those observed in the field. Plants inoculated with the reference strain wilted 7 to 11 days after inoculation. Control plants treated with water remained healthy. R. solanacearum was recovered from the 20 symptomatic plants on TTC medium. The identity of the strains in comparison with the reference strain was confirmed by PCR with species-specific primers 759/760, which produced a single 281-bp fragment (3). Because similar symptoms were being increasingly reported by farmers across Benin and linked with reduced tomato yields, a disease survey was undertaken by IITA in 2006 and 2007. Wilted tomato plants were found across all agro-ecological zones of Benin (3 to 72% of plants per field). Isolates were recovered from the southeastern districts of Adja-Ouèrè, Sakété, Adjohoun, and Dangbo, the southwestern districts of Klouékanmè and Athiémé, the southern districts of Toffo and Bohicon, the central districts of Dassa and Savè, and the northern districts of Malanville and Karimama. Identification of R. solanacearum was confirmed following inoculation of tomato, production of characteristic wilting symptoms, recovery of the pathogen on TTC medium, and positive identification with ELISA kits (Pathoscreen Rs; Agdia Inc., Elkhart, IN). To our knowledge, this is the first report of R. solanacearum infecting tomato in Benin. Tomato is the most cultivated vegetable crop in Benin and important to the livelihood of many people in peri-urban and rural areas. Understanding that the cause of the observed crop losses is R. solanacearum may lead to implementation of management strategies such as deployment of disease-resistant cultivars or grafting tomatoes onto bacterial wilt-resistant rootstocks (1). References: (1) P. Aggarwal et al. Indian J. Agric. Sci. 78:379, 2008. (2) A. Kelman. Phytopathology 44:693, 1954. (3) N. Opina et al. Asian Pac. J. Mol. Biol. Biotechnol. 5:19, 1997.

Common themes emerge in the transcriptional control of T helper and developmental cell fate decisions regulated by the T-box, GATA and ROR families

Cellular differentiation requires the precise action of lineage-determining transcription factors. In the immune system, CD4(+) T helper cells differentiate into at least three distinct effector lineages, T helper type 1 (Th1), Th2 and Th17, with the fate of the cell at least in part determined by the transcription factors T-box expressed in T cells (T-bet), GATA-3 and retinoid-related orphan receptor gammat (RORgammat), respectively. Importantly, these transcription factors are members of larger families that are required for numerous developmental transitions from early embryogenesis into adulthood. Mutations in members of these transcription factor families are associated with a number of human genetic diseases due to a failure in completing lineage-specification events when the factor is dysregulated. Mechanistically, there are both common and distinct functional activities that are utilized by T-box, GATA and ROR family members to globally alter the cellular gene expression profiles at specific cell fate decision checkpoints. Therefore, understanding the molecular events that contribute to the ability of T-bet, GATA-3 and RORgammat to define T helper cell lineages can provide valuable information relevant to the establishment of other developmental systems and, conversely, information from diverse developmental systems may provide unexpected insights into the molecular mechanisms utilized in T helper cell differentiation.

Dynamics of pigmentation induction by repeated ultraviolet exposures: dose, dose interval and ultraviolet spectrum dependence

BACKGROUND

The dynamics of ultraviolet (UV)-induced melanogenesis have been well characterized for single UV exposures. However, our knowledge of the effects of repeated UV exposures on the development of new pigmentation is limited.

OBJECTIVES

To characterize the dynamics and dose dependence of pigmentation induction by repeated UV exposures using two different UV sources.

METHODS

A total of 40 healthy subjects participated in the study: 21 were exposed to a 5% UVB/95% UVA source and 19 were exposed to a 2% UVB/98% UVA source. Skin phototypes 2-3 were represented. Subjects were exposed one to three times per week. The minimal erythemal dose and minimal melanogenic dose of all subjects were determined, and both visual and instrumental observations of the development of pigmentation and erythema were recorded.

RESULTS

Dark-brown pigmentation could be produced by a cumulative UV dose of 4200 J m(-2) given as 10 exposures over 5 weeks. However, comparable pigmentation could also be induced by a cumulative dose of 2900 J m(-2) given as eight exposures over 4 weeks. The lowest cumulative dose of 1900 J m(-2) given over 4 weeks produced moderate pigmentation. The 2% UVB source led to earlier and darker pigmentation than the 5% UVB source did for equally erythemogenic doses.

CONCLUSIONS

These observations show that the dynamics of melanogenesis induced by repeated exposures depends on UV dose, dose interval and emission spectrum. They also indicate that increasing the UV dose above a certain level of cumulative exposure does not significantly increase the level of UV-induced pigmentation.

Chronic high Epstein-Barr viral load state and risk for late-onset posttransplant lymphoproliferative disease/lymphoma in children

Increased use of serial EBV-PCR monitoring after pediatric transplantation has led to the identification of asymptomatic patients who carry very high viral loads over prolonged periods. The significance of this high-load state is unknown. We speculated that this state may identify patients at high risk for development of late PTLD/lymphoma. We reviewed data on 71 pediatric heart recipients who had serial viral load monitoring since 1997. Chronic high-load state was defined as the presence of >16,000 genome copies/mL whole blood on > or =50% of samples over at least 6 months. Among 20 high-load carriers (eight following prior PTLD, seven with prior symptomatic EBV infection, five without previous EBV disease), 9 (45%) developed late-onset PTLD 2.5-8.4 years posttransplant (including with four Burkitt's lymphoma). Among 51 controls with low (n = 39) or absent (n = 12) loads, only 2 (4%; p < 0.001 absent/low vs. high load) developed late PTLD/lymphoma. By multivariable analysis, high-load carrier state (OR = 12.4, 95% CI 2.1-74.4) and prior history of PTLD (OR = 10.7, 95% CI 1.9-60.6) independently predicted late PTLD. A chronic high EBV-load state is not benign and is a predictor of de novo or recurrent PTLD.

Acute effects of naltrexone and GBR 12909 on ethanol drinking-in-the-dark in C57BL/6J mice

RATIONALE

Recently, a simple procedure was described, drinking in the dark (DID), in which C57BL/6J mice self-administer ethanol to the point of intoxication. The test consists of replacing the water with 20% ethanol in the home cage for 2 or 4 h early during the dark phase of the light/dark cycle.

OBJECTIVES

To determine whether the model displays predictive validity with naltrexone, and whether opioid or dopaminergic mechanisms mediate excessive drinking in the model.

MATERIALS AND METHODS

Naltrexone or GBR 12909 were administered via intraperitoneal injections immediately before offering ethanol solutions, plain tap water, or 10% sugar water to male C57BL/6J mice, and consumption was monitored over a 2- or 4-h period using the DID procedure.

RESULTS

Naltrexone (0.5, 1, or 2 mg/kg) dose dependently decreased ethanol drinking but these same doses had no significant effect on the consumption of plain water or 10% sugar water. GBR 12909 (5, 10, and 20 mg/kg) dose dependently reduced the consumption of ethanol and sugar water but had no effect on plain water drinking.

CONCLUSIONS

The DID model demonstrates predictive validity. Both opioid and dopamine signaling are involved in ethanol drinking to intoxication. Different physiological pathways mediate high ethanol drinking as compared to water or sugar water drinking in DID. DID may be a useful screening tool to find new alcoholism medications and to discover genetic and neurobiological mechanisms relevant to the human disorder.

Systemic Modulation of Gene Expression in Tomato by Trichoderma hamatum 382

ABSTRACT A light sphagnum peat mix inoculated with Trichoderma hamatum 382 consistently provided a significant (P = 0.05) degree of protection against bacterial spot of tomato and its pathogen Xanthomonas euvesicatoria 110c compared with the control peat mix, even though this biocontrol agent did not colonize aboveground plant parts. To gain insight into the mechanism by which T. hamatum 382 induced resistance in tomato, high-density oligonucleotide microarrays were used to determine its effect on the expression pattern of 15,925 genes in leaves just before they were inoculated with the pathogen. T. hamatum 382 consistently modulated the expression of genes in tomato leaves. We identified 45 genes to be differentially expressed across the replicated treatments, and 41 of these genes could be assigned to at least one of seven functional categories. T. hamatum 382-induced genes have functions associated with biotic or abiotic stress, as well as RNA, DNA, and protein metabolism. Four extensin and extensin-like proteins were induced. However, besides pathogenesis-related protein 5, the main markers of systemic acquired resistance were not significantly induced. This work showed that T. hamatum 382 actively induces systemic changes in plant physiology and disease resistance through systemic modulation of the expression of stress and metabolism genes.

Development of recombinant adeno-associated virus vectors carrying small interfering RNA (shHec1)-mediated depletion of kinetochore Hec1 protein in tumor cells

Transcript depletion using small interfering RNA (siRNA) technology represents a potentially valuable technique for the treatment of cancer. However, delivering therapeutic quantities of siRNA into solid tumors by chemical transfection is not feasible, whereas viral vectors efficiently transduce many human tumor cell lines. Yet producing sufficient quantities of viral vectors that elicit acute and selective cytotoxicity remains a major obstacle for preclinical and clinical trials. Using the invertebrate Spodoptera frugiperda (Sf9) cell line, we were able to produce high titer stocks of cytotoxic recombinant adeno-associated virus (rAAV) that express short hairpin RNA (shRNA) and that efficiently deplete Hec1 (highly expressed in cancer 1), or Kntc2 (kinetochore-associated protein 2), a kinetochore protein directly involved in kinetochore microtubule interactions, chromosome congression and spindle checkpoint signaling. Depletion of Hec1 protein results in persistent spindle checkpoint activation followed by cell death. Because Hec1 expression and activity are only present in mitotic cells, non-dividing cells were not affected by rAAV treatment. On the basis of the results of screening 56 human tumor cell lines with three different serotype vectors, we used a tumor xenograft model to test the effects in vivo. The effects of the shHec1 vector were evident in sectioned and stained tumors. The experiments with rAAV-shRNA vectors demonstrate the utility of producing vectors in invertebrate cells to obtain sufficient concentrations and quantities for solid tumor therapy. This addresses an important requirement for cancer gene therapy, to produce cytotoxic vectors in sufficient quantities and concentrations to enable quantitative transduction and selective killing of solid tumor cells.

Apoptosis and antigen receptor function in T and B cells following exposure to herpes simplex virus

T cells are an essential component of the immune response against herpes simplex virus (HSV) infection. We previously reported that incubation of T cells with HSV-infected fibroblasts inhibits subsequent T cell antigen receptor signal transduction. In the current study, we found that incubation of T cells with HSV-infected fibroblasts also leads to apoptosis in exposed T cells. Apoptosis was observed in Jurkat cells, a T cell leukemia line, and also in CD4(+) cells isolated from human peripheral blood mononuclear cells. Direct infection of these cells with HSV also resulted in apoptosis. Clinical isolates of both HSV type 1 and 2 induced apoptosis in infected T cells at comparable levels to cells infected with laboratory strains of HSV, suggesting an immune evasion mechanism that may be clinically relevant. Further understanding of these viral immune evasion mechanisms could be exploited for better management of HSV infection.

The effect of gel lubrication on cuff leakage of double lumen tubes during thoracic surgery*

High-volume, low-pressure tracheal cuffs of disposable double lumen tubes may offer limited protection to the dependent lung if fluid leaks through folds in the inflated cuffs. This study was undertaken to determine the incidence of fluid leakage past the tracheal cuff and whether gel lubrication reduces the incidence. Fifty-five patients were randomly assigned to receive a double lumen tube with or without gel lubrication. The dependent lung was intubated. With the patient in the lateral position, methylthionium chloride was administered above the tracheal cuff via a pre-attached catheter. Fibreoptic bronchoscopy was performed to determine if dye had passed the tracheal cuff. Three patients were excluded. Dye leakage was seen in 12/27 and 3/25 patients in the unlubricated and lubricated group, respectively (p = 0.014). Gel lubrication significantly reduces fluid leakage past the tracheal cuff of a double lumen tube and should be considered for all thoracic surgical patients requiring one-lung ventilation.

Restricted MHC-peptide repertoire predisposes to autoimmunity

MHC molecules associated with autoimmunity possess known structural features that limit the repertoire of peptides that they can present. Such limitation gives a selective advantage to TCRs that rely on interaction with the MHC itself, rather than with the peptide residues. At the same time, negative selection is impaired because of the lack of negatively selecting peptide ligands. The combination of these factors may predispose to autoimmunity. We found that mice with an MHC class II–peptide repertoire reduced to a single complex demonstrated various autoimmune reactions. Transgenic mice bearing a TCR (MM14.4) cloned from such a mouse developed severe autoimmune dermatitis. Although MM14.4 originated from a CD4⁺ T cell, dermatitis was mediated by CD8⁺ T cells. It was established that MM14.4⁺ is a highly promiscuous TCR with dual MHC class I/MHC class II restriction. Furthermore, mice with a limited MHC–peptide repertoire selected elevated numbers of TCRs with dual MHC class I/MHC class II restriction, a likely source of autoreactivity. Our findings may help to explain the link between MHC class I responses that are involved in major autoimmune diseases and the well-established genetic linkage of these diseases with MHC class II.

The mechanisms and managements of hormone-therapy resistance in breast and prostate cancers

Breast and prostate cancer are the most well-characterized cancers of the type that have their development and growth controlled by the endocrine system. These cancers are the leading causes of cancer death in women and men, respectively, in the United States. Being hormone-dependent tumors, antihormone therapies usually are effective in prevention and treatment. However, the emergence of resistance is common, especially for locally advanced tumors and metastatic tumors, in which case resistance is predictable. The phenotypes of these resistant tumors include receptor-positive, ligand-dependent; receptor-positive, ligand-independent; and receptor-negative, ligand-independent. The underlying mechanisms of these phenotypes are complicated, involving not only sex hormones and sex hormone receptors, but also several growth factors and growth factor receptors, with different signaling pathways existing alone or together, and with each pathway possibly linking to one another. In this review, we will discuss the potential mechanisms of antihormone-therapy resistance in breast and prostate cancers, especially focusing on the similarities and differences of these two cancers. We will also discuss novel agents that have been applied in clinical practice or with clinical potential in the future.

Multidisciplinary Investigation of Atypical Inclusion Complexes of β-Cyclodextrin and a Phospholipase-A2 Inhibitor

BMS-188184, an anthracene derivative, has been found to form at least two complexes with beta-cyclodextrin. The association/dissociation kinetics of the two complexes were extremely slow, with one complex requiring approximately 24 h, and the other complex requiring more than 8 weeks, to reach equilibrium. The stability constants of the two complexes were estimated at approximately 11,000 and 39,000 M(-1) under nonequilibrium conditions. The slow rates of dissociation allowed the complexes and the unbound BMS-188184 to be separated using high-performance liquid chromatography. Exact mass liquid chromatography/mass spectrometry, tandem mass spectrometry, and nuclear magnetic resonance techniques were used to characterize the stoichiometry of both complexes as 1:1. Because of the ability of the complexes to survive high-performance liquid chromatography analysis, their slow reaction rates, and 1:1 stoichiometry, the complexes were tentatively characterized as [2]-rotaxanes. The available data suggest that the two complexes are conformational isomers.

Systemic Resistance Induced by Trichoderma hamatum 382 in Cucumber Against Phytophthora Crown Rot and Leaf Blight

Phytophthora root rot, crown rot, leaf and stem blight, and fruit rot of cucumber can cause serious losses, and are difficult to control. Although composts can be used successfully for control of Phytophthora root rots, little is known about their effects on Phytophthora diseases of aboveground plant parts. This research shows that the severity of Phytophthora root and crown rot of cucumber caused by Phytophthora capsici was suppressed significantly in cucumber transplants produced in a composted cow manure-amended mix compared with those in a dark sphagnum peat mix. In split root bioassays, Trichoderma hamatum 382 (T₃₈₂) inoculated into the compost-amended potting mix significantly reduced the severity of Phytophthora root and crown rot on paired roots in the peat mix. This effect did not differ significantly from that provided by a drench with benzothiadiazole (BTH) or mefenoxam (Subdue MAXX). Based on area under disease progress curves, T₃₈₂ also significantly reduced the severity of Phytophthora leaf blight in transplants produced in the compost mix compared with controls not inoculated with T₃₈₂. Efficacy of T₃₈₂ did not differ significantly from that provided by a drench with BTH. T₃₈₂ re-mained spatially separated from the pathogen in plants in both the split root and leaf blight bioassays, suggesting that these effects were systemic in nature.

Isolation and structure determination of an antimicrobial ester from a marine sediment-derived bacterium

A new compound, assigned the trivial name bonactin (1), has been isolated from the liquid culture of a Streptomyces sp. BD21-2 obtained from a shallow-water sediment sample collected at Kailua Beach, Oahu, Hawaii. Structure elucidation employed one- and two-dimensional NMR, HRFABMS, IR, and chemical analysis. Bonactin displayed antimicrobial activity against both Gram-positive and Gram-negative bacteria as well as antifungal activity.

Herbal medicines for the treatment of rheumatoid arthritis: a systematic review

OBJECTIVE

With the growing interest in herbal therapies among persons with rheumatoid arthritis, there exists a need for investigation into their safety and efficacy. The purpose of this study was to conduct a systematic review to examine the evidence for the use of herbal medicines for RA based on randomized clinical trials (RCTs).

METHODS

A computerized search of eight electronic databases and the bibliographies of identified articles resulted in 14 studies meeting the inclusion criteria. Two raters independently extracted data and rated the trials for quality.

RESULTS

There is moderate support for gamma-linolenic acid (GLA), which is found in some herbal medicines, for reducing pain, tender joint count and stiffness. For other herbal medicines there was only a single RCT available, resulting in weak evidence. In general, herbal preparations were relatively safe to use.

CONCLUSIONS

Given the number of herbal medicines promoted for RA, further research is needed to examine their efficacy, safety and potential drug interactions.

Resistance of Pepper Cultivars and Accessions of Capsicum spp. to Sclerotinia sclerotiorum

Sclerotinia stem and fruit rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is a potentially serious disease of bell peppers (Capsicum annuum L.), affecting both seedlings and mature plants. Management options for the disease are limited and information is not available on resistance in Capsicum spp. to this pathogen. The level of resistance of 12 commercial pepper cultivars and 110 Capsicum spp. accessions to Sclerotinia sclerotiorum was determined by using limited-term and ascospore inoculation methods. None of the commercial cultivars tested were resistant to Sclerotinia stem rot. Stem rot incidence among the Capsicum spp. accessions tested by ascospore inoculation ranged from 0 to 100%. Fifty-eight accessions had significantly less stem disease than the susceptible commercial cultivar Marengo. There was no correlation between results of the limited-term and ascospore inoculation tests. These results demonstrate for the first time that a high level of Sclerotinia stem rot resistance exists among the Capsicum spp. accessions. Several accessions may be suitable for use in breeding programs to increase resistance in commercial pepper cultivars.

Stress reactivity of the brain noradrenergic system in three rat strains differing in their neuroendocrine and behavioral responses to stress: implications for susceptibility to stress-related neuropsychiatric disorders

The brain noradrenergic system is activated by stress, modulating the activity of forebrain regions involved in behavioral and neuroendocrine responses to stress. In this study, we characterized brain noradrenergic reactivity to acute immobilization stress in three rat strains that differ in their neuroendocrine stress response: the inbred Lewis (Lew) and Wistar-Kyoto (WKY) rats, and outbred Sprague-Dawley (SD) rats. Noradrenergic reactivity was assessed by measuring tyrosine hydroxylase mRNA expression in locus coeruleus, and norepinephrine release in the lateral bed nucleus of the stria terminalis. Behavioral measures of arousal and acute stress responsivity included locomotion in a novel environment, fear-potentiated startle, and stress-induced reductions in social interaction and open-arm exploration on the elevated-plus maze. Neuroendocrine responses were assessed by plasma adrenocorticotropic hormone. Compared to SD, adrenocorticotropic hormone responses of Lew rats were blunted, whereas those of WKY were enhanced. The behavioral effects of stress were similar in Lew and SD rats, despite baseline differences. Lew had similar elevations of tyrosine hydroxylase mRNA, and initially greater norepinephrine release in the lateral bed nucleus of the stria terminalis during stress, although both noradrenergic responses returned toward baseline more rapidly than in SD rats. WKY rats showed depressed baseline startle and lower baseline exploratory and social behavior than SD. However, unlike the Lew or SD rats, WKY exhibited a lack both of fear potentiation of the startle response and of stress-induced reductions in exploratory and social behavior, indicating attenuated stress responsivity. Acute noradrenergic reactivity to stress, measured by either tyrosine hydroxylase mRNA levels or norepinephrine release, was also attenuated in WKY rats. Thus, reduced arousal and behavioral responsivity in WKY rats may be related to deficient brain noradrenergic reactivity. This deficit may alter their ability to cope with stress, resulting in the exaggerated neuroendocrine responses and increased susceptibility to stress-related pathology exhibited by this strain.

Diversity Among Strains of Xanthomonas campestris pv. vitians from Lettuce

ABSTRACT Diversity in host range, pathogenicity, phenotypic characteristics, repetitive extragenic palindromic polymerase chain reaction (rep-PCR) profiles, and sequence of the 16S-23S rDNA spacer region was examined among 44 Xanthomonas strains isolated from lettuce. Forty-two of the strains were divided into two groups, designated A and B. Seventy percent were Group A, and most of the remaining strains including a reference strain (LMG 938) were Group B. Group A strains induced both local and systemic symptoms, whereas Group B strains caused only distinct necrotic spots. Two strains, including the X. campestris pv. vitians type strain, were distinct from the Group A and B strains and were not pathogenic on lettuce. Analysis of fatty acid profiles, serotype, carbon substrate utilization patterns, and protein fingerprints confirmed this grouping. The Group A and B strains also formed two unique clusters (I and II) by rep-PCR profiling that corresponded to the two groups. Direct sequencing of a PCR-amplified DNA fragment (680 bp) from the 16S-23S rDNA spacer region of four representative strains, however, did not differentiate these groups. Serology and rep-PCR fingerprinting can be used to diagnose and identify X. campestris pv. vitians strains, while the other analyses evaluated are useful for strain characterization.

Effect of Rice Root-Knot Nematode on Growth and Yield of Yellow Granex Onion

Rice root-knot nematode, Meloidogyne graminicola, infects all commercially grown onion cultivars in rice-onion cropping systems in the Philippines, but its economic importance has not been established. The effects of different preplant population levels (Pi) of M. graminicolaon Yellow Granex onion in pots and of different percentages of galled roots in a naturally infested field were evaluated. Leaf weight and root length of 'Yellow Granex 429' seedlings decreased with increasing Pi, while low Pi mildly stimulated plant height at the vegetative growth stage. Age of transplant and Pi influenced growth and yield of onion at maturity. Onion yield and root and leaf weights decreased as the age of the transplants increased. Growth and yield decreased with increased Pi. Bulb weight was reduced by 7 to 82% and diameter by 10 to 62% when plants were inoculated with 50 to 10,000 second-stage juveniles. Onion bulbs from the field were reduced by 16, 32, and 35% in weight and by 6, 17, and 18% in diameter when the percentage of roots galled was 10, 50, and 100%, respectively. Management of M. graminicolapopulations at the start of the growing season must be part of onion culture in rice-onion systems to reduce onion yield losses and to prevent economic loss.

Integrating evidence-based decision making into allied health curricula

An evidence-based approach may decrease variations in practice and time delays in adopting new procedures. This report describes the process for incorporating evidence-based decision making (EBDM) into curricula using active teaching techniques. The process centers on a national four-day Faculty Development Institute (FDI) program for dental hygiene, occupational therapy, and physical therapy faculty. Phase I assesses pre-Institute EBDM knowledge, skills, and teaching strategies. Phase II, onsite, involves learning EBDM principles and teaching skills and developing an educational package. Phase III integrates these into the curriculum, with ongoing follow-up. At baseline, faculty were unfamiliar with EBDM but were incorporating related skills. Formulation of questions and evidence gathering for patient-care decisions were weak. Phase II follow-up showed a significant increase in EBDM knowledge, p < 0.001, and 100% agreed or strongly agreed that they were prepared to integrate EBDM into their courses; 93% felt better prepared to use EBDM. Curricula and educational experiences need to include EBDM skills. The three-phase process can support faculty in making needed changes.

Report of Bacterial Leaf Spot on Collards and Turnip Leaves in Ohio

In 2000, circular water-soaked lesions typical of bacterial leaf spot were observed on leaves of collards (Brassica oleracea L. var. viridis) throughout commercial fields in northwest Ohio. Light brown, rectangular, water-soaked lesions were observed on turnip leaves (Brassica rapa L.). Bacterial streaming from lesions on both crops was observed microscopically. Cream colored, fluorescent colonies were isolated from diseased tissues on Pseudomonas F medium, and eight representative colonies (four from collards and four from turnip) were selected and purified. Fatty acid methyl ester analysis was performed on all of the isolates. Two from collards and two from turnip were identified as Pseudomonas syringae pv. maculicola (mean similarity index = 0.82 [MIDI Inc., Newark, DE]). DNA extracts from pure cultures of the P. syringae pv. maculicola strains were used as template in a polymerase chain reaction (PCR) assay with primers derived from the region of the coronatine gene cluster controlling synthesis of the coronafacic acid moiety found in P. syringae pv. tomato and P. syringae pv. maculicola (CorR and CorF2) (D. Cuppels, personal communication). DNA from P. syringae pv. tomato strain DC3000 and P. syringae pv. maculicola strain 88-10 (2) served as positive controls, while water and DNA from Xanthomonas campestris pv. vesicatoria strain Xcv 767 were used as negative controls. The expected 0.65-kb PCR product was amplified from three of four strains (two from turnip and one from collards) and the positive control DNA, but not from the negative controls. Pathogenicity tests were performed twice on 6-week-old turnip ('Forage Star', 'Turnip Topper', 'Turnip Alamo', 'Turnip 7'), collard ('Champion') and mustard (Brassica juncea L. 'Southern Giant Curl') seedlings using the three PCR-positive strains. Premisted seedlings were spray-inoculated separately with each of the three strains (2 × 10⁸ CFU/ml, 5 ml per plant) and a water control. Greenhouse temperatures were maintained at 20 ± 1°C. For both tests, all strains caused characteristic lesions on all of the crucifer cultivars within 5 days after inoculation; the control plants did not develop symptoms. To satisfy Koch's postulates, one of the turnip strains was reisolated from 'Turnip Topper' plants, and the collard strain was reisolated from 'Champion' plants. The three original and two reisolated strains induced a hypersensitive response in Mirabilis jalapa L. and Nicotiana tabacum L. var. xanthia plants 24 h after inoculation with a bacterial suspension (1 × 10⁸ CFU/ml). The original and reisolated strains were compared using rep-PCR with the primer BOXA1R (1). The DNA fingerprints of the reisolated strains were identical to those of the original strains. To our knowledge, this is the first report of bacterial leaf spot on commercially grown collards and turnip greens in Ohio. References: (1) B. Martin et al. Nucleic Acids Res. 20:3479, 1992. (2) R. A. Moore et al. Can. J. Microbiol. 35:910, 1989.