A leaf spot and blight of greenhouse tomato seedlings incited by a Herbaspirillum sp.

A leaf spot and blighting were observed on leaves of tomato transplants from a producer in Florida in 2001 and 2002. A nonfluorescent bacterium was isolated consistently from affected tissue. The typical bacterium was a gram negative, strictly aerobic, slightly curved rod with one or two flagella. Sequence analysis of the 16S rRNA indicated that two representative strains, F1 and SE1, had greater than 99% nucleotide sequence identity with Herbaspirillum huttiense and H. rubrisubalbicans. The cellular fatty acid composition of the total of 16 tomato strains was very similar to H. huttiense and H. rubrisubalbicans. Based on carbon utilization, six of nine strains tested with the Biolog system were identified as Herbaspirillum spp. The tomato strains were oxidase positive and grew at 40 degrees C, but were negative for levan production, pectate hydrolysis, and arginine dihydrolase activity. Based upon this polyphasic analysis, we concluded that the strains were most closely related to H. huttiense, although placement in this species would require further analyses. However, the tomato strains and H. rubrisubalbicans, but not H. huttiense, caused confluent necrosis when infiltrated at high concentrations into tomato leaves and were able to produce leaf spot symptoms on inoculated tomato seedlings in the greenhouse. Using pulsed-field gel electrophoresis, we determined that there was considerable variability between the strains collected in 2001 and 2002

Deficits in attention to emotional stimuli distinguish youth with severe mood dysregulation from youth with bipolar disorder.

Studying attention in the context of emotional stimuli may aid in differentiating pediatric bipolar disorder (BD) from severe mood dysregulation (SMD). SMD is characterized by chronic irritability, arousal, and hyper-reactivity; SMD youth frequently receive a BD diagnosis although they do not meet DSM-IV criteria for BD because they lack manic episodes. We compared 57 BD (14.4 +/- 2.9 years old, 56% male), 41 SMD (12.6 +/- 2.6 years old, 66% male), and 33 control subjects (13.7 +/- 2.5 years old, 52% male) using the Emotional Interrupt task, which examines how attention is impacted by positive, negative, or neutral distracters. We compared reaction time (RT) and accuracy and calculated attention interference scores by subtracting performance on neutral trials from emotional trials. Between-group analyses indicated that SMD subjects had significantly reduced attention interference from emotional distracters relative to BD and control subjects. Thus, attention in SMD youth was not modulated by emotional stimuli. This blunted response in SMD youth may contribute to their affective and behavioral dysregulation

Pseudomonas huttiensis Associated with Leaf Necrosis and Blighting of Tomato Seedlings in the Greenhouse

In October 2001, tomato foliage with blighting and a leaf spot was received from a transplant producer in Florida. The seedlings manifested apical or marginal leaf necrosis or discrete lesions along the leaf veins. Non-fluorescent bacterial strains forming viscous, creamy white colonies on King's medium B and causing a hypersensitive reaction in tomato and pepper leaves was consistently isolated from lesions. Pathogenicity was checked on three-week old tomato plants. The plants were incubated in high humidity for 24 h before and after inoculation. Similar symptoms were observed on the inoculated seedlings. We characterised 12 strains using bacteriological tests. According to the fatty acid profile, the strains displayed highest similarity with the bacterium Pseudomonas huttiensis Leifson 1962. Sequence analysis of the 16S rRNA indicated that this bacterium shows 98.7divided by98.8% homology with two Herbaspirillum species. Thus, our strains were compared with one P. huttiensis and five H. rubrisubalbicans strains. The strains from tomato were Gram-negative, non-fluorescent and oxidase positive, but levan, pectate hydrolysis and arginine dihydrolase negative, and grew at 40degreesC. Based on these results, they had a high degree of similarity with both P. huttiensis and H. rubrisubalbicans

Exploring diversity of Erwinia amylovora population in Serbia by conventional and automated techniquesand detection of new PFGE patterns

Forty Erwinia amylovora strains originating from different host plants and locations in Serbia and one strain from Montenegro were characterized by conventional, automated and molecular techniques. All strains were Gram-negative, nonfluorescent, facultative anaerobes, oxidase negative, levan positive, produced necrotic lesions followed by bacterial exudate on artificially inoculated immature pear fruits and caused HR on tobacco. Based on carbon source utilization, all strains tested with the Biolog system were identified as E. amylovora. Based on fatty acid profiles all tested strains clustered into three groups in which strains from north Serbia differed from strains isolated in central and south parts of the country. Restriction analysis of genomic DNA using XbaI and PFGE resulted in six different patterns differentiating the strains into six groups. Most of the investigated strains clustered in one group having the pattern type similar to Pt2 group described earlier as dominant in East Europe and the Mediterranean region. Two strains showed PFGE pattern similar to the previously described Pt3 pattern and one strain had pattern similar to Pt6. Based on size and number of the bands, new restriction patterns, assigned as Pt7, Pt8 and Pt9 were observed. PFGE results showed that the E. amylovora population in Serbia is not homogenous and was possibly introduced from different directions. This is the first characterization of E. amylovora collection of strains from Serbia using fatty acid analysis and PFGE

Exploring diversity of Erwinia amylovora population in Serbia by conventional and automated techniques and detection of new PFGE patterns

Forty Erwinia amylovora strains originating from different host plants and locations in Serbia and one strain from Montenegro were characterized by conventional, automated and molecular techniques. All strains were Gram-negative, nonfluorescent, facultative anaerobes, oxidase negative, levan positive, produced necrotic lesions followed by bacterial exudate on artificially inoculated immature pear fruits and caused HR on tobacco. Based on carbon source utilization, all strains tested with the Biolog system were identified as E. amylovora. Based on fatty acid profiles all tested strains clustered into three groups in which strains from north Serbia differed from strains isolated in central and south parts of the country. Restriction analysis of genomic DNA using XbaI and PFGE resulted in six different patterns differentiating the strains into six groups. Most of the investigated strains clustered in one group having the pattern type similar to Pt2 group described earlier as dominant in East Europe and the Mediterranean region. Two strains showed PFGE pattern similar to the previously described Pt3 pattern and one strain had pattern similar to Pt6. Based on size and number of the bands, new restriction patterns, assigned as Pt7, Pt8 and Pt9 were observed. PFGE results showed that E. amylovora population in Serbia is not homogenous and was possibly introduced from different directions. This is the first characterization of E. amylovora collection of strains from Serbia using fatty acid analysis and PFGE

Identification and Differentiation of Erwinia amylovora Using Fatty Acid Analysis and BIOLOG

A collection of 41 Erwinia amylovora strains isolated from 8 plant species at 13 locations in Serbia and one location in Montenegro was tested and their relationship was determined based on carbohydrate metabolism and fatty acid composition. Metabolism of carbon compounds was tested using the Biolog GN MicroPlate system. After 24 h of incubation, the resulting metabolic fingerprints were recorded and compared with the Biolog GN database. Fatty acid composition was analyzed by Microbial Identification System and compared with the data from the MIDI database. Our results showed that all strains tested were identified as E. amylovora, with similarity index (SI) between 0.62 and 0.99, using BIOLOG. Based on fatty acid composition, 39 strains were identified as E. amylovora, with SI between 0.61 and 0.92. More than 14 fatty acids were detected, eight of which were present in all strains with more than 1% of the total named peak area. Based on quantitative and qualitative content of fatty acid composition, the isolates were clustered into three groups: alpha, beta and gamma (Euclidian distance lt = 6). Cluster analysis revealed that groups beta and gamma consists of only strains isolated from north Serbia, whereas all strains isolated from central or south Serbia belong to group alpha