Genes cry de Bacillus thuringiensis aplicados na engenharia genética de plantas, conferindo resistência a insetos-praga

This study presents a bibliographic synthesis about the entomopathogen Bacillus thuringiensis and the cry genes application on the genetic engineering of cultivated crops which codify insecticide proteins. Over the last decade, the importance of the transgenic crops – named Bt crops – has increased commercially, leading them to take the second place among genetically modified (GM) crops most used and distributed. In the last harvest (2006), total Bt crops reached 19 million hectares worldwide, and the Bt-corn already presented 16 commercial approvals, given that the first commercial Bt-rice plantation was made in Iran, 2005. The clean technology development, such as GM cultivars, presents several advantages in comparison to formulated insecticides, which depends on appropriated application methods according to the crop culture or the insect behavior, and the impacts over the nontarget organisms and the environment. In this sense, the Btrice has the potential to increase productivity, decrease the pesticide application and thus improve the environmental quality on the agricultural systems, which are highly related to environment conservation areas such as flooded regions of Rio Grande do Sul. The potential benefits that Bt-rice can offer, based on already obtained results with Bt-cotton and Bt-corn, should motivate new researches and the development of different varieties of Bt-rice. As a result, it could accelerate the approval and release of this technology to the rice farmers. Key words: Bacillus thuringiensis, insects, cry genes, transgenic plants.Este trabalho apresenta uma síntese de pesquisa bibliográfica sobre o entomopatógeno Bacillus thuringiensis e a aplicação dos seus genes cry – que codificam proteínas inseticidas – na engenharia genética de plantas cultivadas. Na última década, a importância das cultivares transgênicas, denominadas plantas-Bt, têm crescido comercialmente, fato que as leva a ocupar o segundo lugar entre as plantas geneticamente modificadas (GM), devido aos índices de maior emprego e distribuição. Na última safra (2006), o total de plantas-Bt atingiu 19 milhões de hectares e, no âmbito mundial, o milho-Bt apresentou 16 aprovações comerciais, se comparado ao primeiro plantio comercial de arroz-Bt, efetuado em 2005, no Irã. O desenvolvimento de tecnologias limpas, como os cultivares GM, apresenta diversas vantagens em relação aos inseticidas formulados, os quais dependem de métodos adequados de aplicação, conforme a cultura ou o modo de vida do inseto, e causam impacto a organismos não alvo e ao ambiente. Nesse sentido, o arroz-Bt tem o potencial de aumentar a produtividade, diminuir a aplicação de pesticidas e, conseqüentemente, melhorar a qualidade ambiental nas áreas de cultivo, as quais estão interligadas a áreas de conservação ambiental, como as regiões inundadas do Rio Grande do Sul. Os potenciais de benefícios que o arroz-Bt pode oferecer, com base nos resultados já obtidos com o algodão-Bt e o milho-Bt, devem se tornar motivadores para as novas pesquisas e para o desenvolvimento de diferentes cultivares de arroz-Bt. Assim, será possível acelerar a aprovação e a liberação dessa tecnologia aos orizicultores. Palavras-chave: Bacillus thuringiensis, insetos, genes cry, plantas transgênicas

Development of a freeze-dried symbiotic obtained from rice bran

This study aimed to assess the growth potential of L.acidophilus and L.plantarum in rice bran, a co-product from the food industry, and subsequently develop a freeze-dried symbiotic. Furthermore, phytochemicals and antioxidant properties were analysed. The growth was measured using growth kinetics over 72 h. The total phenolic compounds were analysed by the Folin-Ciocalteau method and antioxidant potential by DPPH and ABS methods. Freeze-drying process occurred using a pilot-scale equipment (Liotop LP510), verification and quantification of probiotics occurred through molecular analyses, as DNA extraction and qPCR. As a result, there was a good growth in rice bran (p = 0.04), suggesting its prebiotic potential. Rice bran also showed significant concentrations of phenolic compounds (3.69 mgEAG/mL ± 0.04) and antioxidant activity according ABTS (8.35 μmol ET/mL ± 0.106) and DPPH (24.71 μmol ET/mL ± 7.90) methods. The bacteria concentration decreased significantly when submitted to the freeze-drying process (p = 0.001), however, they remained by the minimum concentration required for a product to be considered a symbiotic. Therefore, it was concluded that rice bran and these analysed bacteria proved to be effective for a symbiotic formulation

Sensory Profile, Consumer Preference and Chemical Composition of Craft Beers from Brazil

Craft beers are known for their distinct flavor, brew, and regional distribution. They are made using top-fermenting (ale) yeast, bottom-fermenting (lager) yeast, or through spontaneous fermentation. Craft beers are consumed and produced in Brazil in large quantities. However, they present a high level of polyphenols, which affects consumer preference as they may yield a taste of bitterness to beers. In this study, we analyzed the relationship between polyphenols and bitterness as well as the composition of the main styles of craft beers and consumer preference for them. Six different styles were analyzed according to their polyphenol content, bitterness, chemical composition, sensory profile, and preference. For preference, a panel of 62 untrained assessors was used. For sensory profile, quantitative descriptive analysis was performed using expert assessors (n = 8). The most preferred style was classic American pilsner, and the least preferred was standard American lager. The most preferred style showed less bitterness (9.52) and lower polyphenol content (0.61 mg EAG/mL), total solids (6.75 °Brix), and turbidity (7.27 NTU). This beer also exhibited reduced sensory notes of malty, fruity, smoked, hoppy, and phenolic but a higher perception of floral, sweet, and yeast notes; the bitterness attribute had a reduced perception. This study advances the understanding and complexity of the sensory profile of different styles of craft beers from Southern Brazil