Aerosol delivery of trail pheromone disrupts the foraging of the red imported fire ant,Solenopsis invicta

BACKGROUND: The fire ant, Solenopsis invicta, is one of the most aggressive and invasive species in the world. The trail pheromone Z,E‐α‐farnesene (91% purity) was prepared, and disruption of worker trail orientation was tested using an ethanol‐based aerosol formulation presenting a single puff of this compound by airbrush and compressed air. Trail‐following behaviour was recorded by overhead webcam and ants digitised before and after presentation of the aerosol treatment at four rates (1.6, 16, 160 and 1600 ng cm^?2). RESULTS: Ants preferred 110 ng cm^?1 over 11, 1.1 and 0.11 ng cm^?1 for trail following. Within seconds of presentation of 1600 ng cm^?2, the highest dose tested, trail disruption was observed. Disruption was evident as reduced arrival success and reduction in the trail integrity statistic (r²), as well as increased deviation from the trail (deg). The distribution of walking track angles was also flattened. CONCLUSIONS: The feasibility of using aerosol for delivery of trail pheromone was demonstrated, but the need for high purity combined with the difficulty of commercial supply makes this technique impractical. However, the commercial production of Z,E‐α‐farnesene of high purity by industrial biotechnology or from (E)‐nerolidol may be possible in future, which would facilitate further development of trail pheromone disruption of S. invicta. Copyright © 2012 Society of Chemical Industry     

The use of digital image analysis and real‐time PCR fine‐tunes bioassays for quantification of Cercospora leaf spot disease in sugar beet breeding

Cercospora leaf spot, caused by the fungus Cercospora beticola, is a major fungal sugar beet disease worldwide and the cause of significant yield losses. The disease is most successfully countered by the introduction of genetic tolerance into elite sugar beet hybrids. To this end, breeding programmes require high quality biological assays allowing discrimination of minor differences between plants within a segregating population. This study describes the successful implementation of image analysis software in the bioassays for quantification of necrotic lesions at different stages of C. beticola infection, allowing selection on minor phenotypic differences during the sugar beet breeding process for C. beticola resistance. In addition, a real‐time PCR assay was developed for the quantification of C. beticola pathogen biomass in infected beet canopy. The use of both techniques, even in an early stage of infection, fine‐tunes current bioassays, allowing more accurate and efficient selection of resistant breeding material.     

Resistance to Pseudomonas syringae in a collection of pea germplasm under field and controlled conditions

A total of 242 Pisum accessions were screened for resistance to Pseudomonas syringae pv. pisi under controlled conditions. Resistance was found to all races, including race 6 and the recently described race 8. Fifty‐eight accessions were further tested for resistance to P. syringae pv. syringae under controlled conditions, with some highly resistant accessions identified. Finally, a set of 41 accessions were evaluated for resistance to P. syringae pv. pisi and pv. syringae under spring‐ and winter‐sowing field conditions. R2, R3 and R4 race‐specific resistance genes to P. syringae pv. pisi protected pea plants in the field. Resistance sources to race 6 identified under controlled conditions were ineffective in the field. Frost effects were also evaluated in relation to disease response. Results strongly suggest that frost tolerance is effective in lowering the disease effects caused by P. syringae pv. pisi and pv. syringae under frost‐stress conditions, even in the absence of disease resistance genes, although the highest degree of this protection is reached when frost tolerance and disease‐resistance genes are combined in the same genetic background.     

The use of two complementary DNA assays,AFLP and MLSA,for epidemic and phylogenetic studies of pectolytic enterobacterial strains with focus on the heterogeneous species Pectobacterium carotovorum

Amplified fragment length polymorphism (AFLP) markers and multilocus sequence analysis (MLSA) were used to analyse 63 bacterial strains, including 30 soft‐rot‐causing bacterial strains collected from Syrian potato fields and 33 reference strains. For the MLSA, additional sequences of 41 strains of Pectobacterium and Dickeya, available from the NCBI GenBank, were included to produce a single alignment of the 104 taxa for the seven concatenated genes (acnA, gapA, proA, icd, mtlD, mdh and pgi). The results indicate the need for a revision of the previously classified strains, as some potato‐derived Pectobacterium carotovorum strains were re‐identified as P. wasabiae. The strains that were classified as P. carotovorum during the analyses demonstrated high heterogeneity and grouped into five P. carotovorum highly supported clusters (PcI to PcV). The strains represented a wide range of host plants including potatoes, cabbage, avocados, arum lilies, sugar cane and more. Host specificity was detected in PcV, in which four of the six strains were isolated from monocotyledonous plants. The PcV strains formed a clearly distinct group in all the constructed phylogenetic trees. The number of strains phylogenetically classified as subspecies ‘P. c. subsp. brasiliensis’ in PcIV dramatically increased in size as a result of the characterization of new isolates or re‐identification of previous P. carotovorum and P. atrosepticum strains. The P. carotovorum strains from Syria were grouped into PcI, PcII and PcIV. This grouping indicates a lack of correlation between the geographical origin and classification of these pathogens.     

Molecular characterization and diagnostics of stubby root and virus vector nematodes of the family Trichodoridae (Nematoda: Triplonchida) using ribosomal RNA genes

Plant parasitic nematodes of the family Trichodoridae cause substantial yield losses in many agricultural crops. Rapid and accurate identification of trichodorids to the species level is critical for selection of appropriate measures for control. This study analysed 99 sequences of the D2–D3 expansion segments of the 28S rRNA gene and 131 sequences of the 18S rRNA gene from the stubby nematodes belonging to the genera Nanidorus, Paratrichodorus and Trichodorus. Species delimiting was based on the integration of morphological identification, which is not provided in the present article, and molecular‐based phylogenetic inference and sequence analysis. Twenty‐two valid species and several species complexes were identified among nematodes included in the analysis. PCR‐RFLPs of the partial 18S rDNA and the D2–D3 expansion segments of the 28S rDNA were tested and proposed for identification of these nematodes. Gel PCR‐RFLP profiles and tables with restriction fragment lengths for several diagnostic enzymes are provided for identification. Some problems of taxonomy and phylogeny of nematodes of the family Trichodoridae are also discussed.     

犬TfR胞外区密码子的优化、真核表达及与犬细小病毒VP2蛋白结合

为制备大量具有天然活性的犬胞外区可溶性转铁蛋白受体(sTfR),本试验通过密码子优化提高sTfR在真核细胞中的表达水平.利用RT-PCR方法从犬肝脏中扩增sTfR编码基因,依据该基因编码的氨基酸序列,参照人偏爱的密码子,对该基因进行密码子优化并由公司合成.利用peDNA3.1-CD5质粒分别构建野生型和密码子优化的sTfR基因真核表达载体,经磷酸钙介导使其在HEK293T细胞中进行表达,利用Western-blotting鉴定表达产物,通过ELISA检测重组犬sTfR蛋白与犬细小病毒VP2蛋白的结合活性.结果显示本试验扩增的犬sTfR基因与GenBank该基因序列的同源性为100%;通过在HEK 293T细胞中进行瞬时表达,结果显示密码子优化可以明显提高sTfR基因在HEK 293T细胞中的表达水平,提高了75%.同时表达的sTfR蛋白能够与犬细小病毒VP2蛋白进行特异结合,表明表达的重组sTfR蛋白具有天然活性.     

Treatment of oral squamous cell carcinoma in a horse by surgical debulking followed by metronomic chemotherapy

A 19‐year‐old Quarter Horse gelding presented with a 6‐week history of hypersalivation, halitosis and dysmasesis. Oral examination revealed retention of food and saliva and the presence of a raised, nodular, 6 × 7 cm, ulcerated mass on the dorsal surface of the tongue base. The mass was confirmed histologically as squamous cell carcinoma. Complete resection of the mass was not possible and surgical laser debulking was followed 15 days later by chemotherapy with a combination of meloxicam and cyclophosphamide in metronomic regimen. After one week, there was a significant improvement in clinical signs and food consumption returned to normal. Therapy was well tolerated with no alteration in haematological or urinalysis parameters. After 5 months of excellent life quality, the horse showed progressive difficulties in mastication and swallowing. Endoscopic examination showed extension of the tumour to all the aboral aspect of the tongue and, with the owner's consent, the patient was subjected to euthanasia. This is believed to be the first report on the combined use of meloxicam and cyclophosphamide in a metronomic fashion for management of an oral squamous cell carcinoma in a horse. Since metronomic therapy is less expensive than conventional chemotherapy, easily administrable and well tolerated, it should be considered as a possible treatment option for nonresectable equine malignant tumours.