Resistance of Soybean Genotypes to Bemisia tabaci (Genn.) Biotype B (Hemiptera: Aleyrodidae)

The silverleaf whitefly Bemisia tabaci (Genn.) biotype B has become a serious problem for soybean cultivation because it can significantly reduce soybean productivity. The use of soybean cultivars resistant to whitefly attack is an important strategy in an integrated pest management (IPM) program. This study evaluated the preference for oviposition and colonization by B. tabaci biotype B on different soybean genotypes. In the free-choice test, the genotypes studied were 'IAC 17' and 'IAC 19' as the standards for resistance and 'IAC Holambra Stwart' as the standard for susceptibility, as well as BABR01-0492, BABR01-0173, BABR01-1259, BABR01-1576, BABR99-4021HC, BABR99-4021HP, 'Barreiras', 'Conquista', 'Corisco', 'BRS Gralha', PI274454, PI227687, and PI171451. In the no-choice test, the four best genotypes selected in the free-choice test, in addition to the susceptible and resistant standards were evaluated. Our data indicated 'Barreiras' as the most resistant genotype against B. tabaci biotype B. 'BRS Gralha', which was the least attractive to whitefly adults in the free-choice test, did not show resistance to insect attack when they were confined in cages in the no-choice test. Despite the high number of eggs observed, BABR01-1576 and BABR99-4021HC showed a reduced number of nymphs, indicating antibiosis. The genotypes with a high level of resistance can be used as a tool against B. tabaci in IPM or as a source of resistance in plant-breeding programs.

Evaluating the Allergic Risk of Genetically Modified Soybean

Genetically modified (GM) soybean (carrying the EPSPS transgene) is the most common GM food in Korea. In order to assess whether genetic modification increases the allergenic risk of soybeans, the allergenicity and IgE-reactive components of wild-type and GM soybean extracts were compared in allergic adults who had been sensitized to soybeans. We enrolled 1,716 adult allergy patients and 40 healthy, non-atopic controls. Skin prick tests and IgE enzyme linked immunosorbent assays (ELISAs) were performed using wild-type and GM soybean extracts, along with other common inhaled allergens. The specificities of serum IgE antibodies from allergic patients and the identities of the IgE-reactive components of the soybean extracts were compared using ELISA inhibition testing, 2-dimensional gel electrophoresis, and IgE immunoblotting. To evaluate the effects of digestive enzymes and heat treatment, the soybean extracts were heated or pre- incubated with or without simulated gastric and intestinal fluids. The IgE sensitization rates to wild-type and GM soybeans were identical (3.8% of allergic adults), and circulating IgE antibodies specific for the two extracts were comparable. The results of the ELISA inhibition test, SDS-PAGE, and IgE immunoblotting showed a similar composition of IgE-binding components within the wild-type and GM extracts, which was confirmed using two-dimensional gel electrophoresis, IgE immunoblotting, and amino acid sequencing. None of the subjects had a positive response to purified EPSPS protein in the skin prick test, ELISA, or IgE immunoblot analysis. These findings suggest that the IgE sensitization rate to GM soybean extracts is identical to that of wild-type soybean extracts in adult allergy patients. In addition, based on both in vivo and in vitro methods, the allergenicity of wild type and GM soybean extracts was identical.

Food Sensitization in Infants and Young Children with Atopic Dermatitis

Atopic dermatitis (AD) is a chronic, relapsing, inflammatory skin disease. Children with AD tend to have a higher prevalence of food allergies. This study investigated the clinical significance of food sensitization in AD patients. A total of 266 AD patients participated in this study. The prevalence of food sensitization and clinically relevant sensitization were compared in the subjects according to their age and AD severity. Sera from all patients were analyzed for food-specific IgE levels using the Pharmacia CAP System FEIA. The serum specific IgE levels for egg, milk, peanut and soybean were measured. Patients were regarded as sensitized to the food if their food-specific IgE levels were above 0.35 kUA/L. Also the food-specific IgE levels, the so-called diagnostic decision point, which is recommended as the clinically relevant level, for clinical food allergy, as suggested by Sampson et al, was used as an alternative method. From the measurement of food-specific IgE antibodies of the four foods, egg was the most highly sensitized and the main causative allergenic food in children with AD. The positive rates of specific IgE to the four major food allergens, and the prevalences of clinically relevant food sensitization, were higher for all foods tested in the group less than 1 year of age, and were significantly higher in moderate to severe AD compared to mild AD in infants and young children. In summary, presence of food specific IgE is prevalent in infants and young children with AD, and clinically relevant food sensitization is important in Korean infants and children with moderate to severe AD.

Comparison of Skin Prick Test Results between Crude Allergen Extracts from Foods and Commercial Allergen Extracts in Atopic Dermatitis by Double-Blind Placebo- Controlled Food Challenge for Milk, Egg, and Soybean

Skin Prick Test (SPT's) are performed to identify the causes of allergy. However, low diagnostic accuracy is a limitation to SPT, for which many possible causes have been suggested. The protein composition and allergenicity of crude allergen extracts from foods and commercial allergen extracts for SPT were analyzed. Clinical significances of SPT using crude allergen extracts from foods were compared with those using commercial allergen extracts. A total of 292 atopic dermatitis patients were involved in this study. Crude allergen extracts were prepared from milk, egg white, egg yolk, and soybean. The protein composition of food allergen extracts and commercial allergen extracts of milk, whole egg, white, egg yolk, and soybean were compared by SDS-PAGE. The allergenicity was tested by the immunoblotting method using immune sera. SPTs were performed using crude and commercial allergen. Double-blind placebo- controlled food challenge (DBPCFC) was performed to verify the SPT results and to compare the clinical significance of crude and commercial allergen extracts. Protein composition differed markedly between crude and commercial allergen extracts. By immunoblotting, crude and commercial allergen extracts showed different allergenicity. The SPT results using crude and commercial allergen extracts showed significant differences. The prevalence of milk, egg and soybean allergy was over 35% in atopic dermatitis. The accuracy of SPT using crude allergen extracts from foods was significantly higher than that using commercial allergen extracts. In the case of soybeans, the result of SPT using commercial allergen extract was clinically insignificant for the prediction of soybean allergy. The source of allergen extract was very important for the appropriate SPT in food allergy. The accuracy of SPT might be improved using the appropriate allergen source for food allergy.

Avaliaçäo do potencial alergênico de um novo produto fermentado de soja / Evaluation of allergenic potential of a novel fermented soymilk product

O processo fermentativo induz uma reduçäo no pH do meio e, dependendo do cultivo bacteriano, observa-se uma açäo proteolítica com diminuiçäo da alergenicidade presente em algumas fraçöes protéicas da soja. No presente estudo, o objetivo foi avaliar o potencial alergênico induzido pela ingestäo oral de um novo produto fermentado de soja, buscando demonstrar a relaçäo existente entre o processo fermentativo e a alergenicidade. Trinta ratos Wistar, machos, adultos, foram separados em cinco grupos: 1. animais tratados com produto fermentado; 2. animais tratados com o produto näo fermentado (placebo); 3. animais sensibilizados com ovalbumina (controle positivo); 4. animais sem nenhum tratamento (somente soluçäo de Tyrode; controle negativo) e 5. animais estimulados pela açäo direta do produto fermentado, placebo e soluçäo de Tyrode. Os produtos fermentados e placebo foram obtidos de acordo com Rossi, et al. No exsudato peritoneal foi determinado o percentual de liberaçäo de histamina e concomitantemente, no mesmo animal, foi verificada a degranulaçäo de mastócitos. Os resultados mostraram que o produto fermentado apresentou um percentual de liberaçäo de histamina (12,6 ñ 2,1 por cento) e degranulaçäo de mastócitos (2,92 ñ 0,9 por cento) menores que o observado para o placebo (18,95 ñ 3,2 por cento e 5,5 ñ 2,3 por cento, respectivamente). Concluiu-se que o produto fermentado näo apresentou potencial alergênico e que o processo fermentativo reduziu favoravelmente a alergenicidade e que o processo fermentativo reduziu favoravelmente a alergenicidade das proteinas de soja.