Abstract The cheese whey shows an organic nutrient charge that can be used to obtain metabolites of interest by biotechnology of microorganisms. Thus, fermentative processes for enzyme production, in particular beta-galactosidase becomes feasible. The enzyme plays an important role in the biotech food industry to obtain milk and dairy products with low lactose content for consumption by intolerant individuals. The objective of this work was to determine the enzyme activity of the concentrated beta-galactosidase (CBG) and the permeabilized cells (PC) both obtained from Saccharomyces fragilis IZ 275. The enzyme beta-galactosidase obtained from the fermentation of Saccharomyces fragilis IZ 275 in cheese whey was used to determine the optimal conditions for the hydrolysis of lactose solution at 1% (w/v). Response Surface Methodology (RSM) by Box-Behnken Design (BBD) was employed to determine beta-galactosidase activity for such factors pH, temperature and enzyme concentration suitable for the lactose hydrolysis. Based on the statistical analysis, the optimum operational conditions for maximizing lactose hydrolysis thus optimizing the enzyme activity for CBG were, temperature 30 °C, pH 6.0 and enzyme concentration 3% (v/v) and for PC was temperature 44 °C, pH 7.0 and enzyme concentration 4% (v/v).

The aim of this work was to evaluate pH values fall rate in chicken breast meat under commercial refrigeration processing conditions and the development of PSE (pale, soft, exudative) meat. Broiler breast samples from the Cobb breed, both genders, at 47 days of age (n = 100) were taken from refrigerated carcasses (RS) immersed in water and ice in a tank chilled at 0°C (±2). pH and temperature (T) values were recorded at several periods throughout refrigeration in comparison to samples left at room T as control (CS). The ultimate pH (pHu) value of 5.86 for RS carcasses were only reached at 11°C after 8.35 h post mortem (PM) while, for CS samples, pHu value was 5.94 at 22°C after 4.08 h PM. Thus, under commercial refrigeration conditions, the glycolysis rate was retarded by over 4.0 h PM and the breast meat color was affected. At 24.02 h PM, PSE meat incidence was 30% while for CS, meat remained dark and PSE meat was not detected. Results show retardation in the glycolysis rate and PSE meat development was promoted by the refrigeration treatment when compared with samples stored at processing room temperature.

Amostras do músculo Pectoralis major foram coletadas e uma RT-PCR foi conduzida para avaliar a sequência do mRNA do αRYR, região compreendida entre os resíduos de aminoácido 386-540, numerado de acordo com a sequência de perus. Os resultados revelaram duas classes de transcritos. O primeiro teve 97% e 74% de identidade com as sequências de αRyR e RyR1 de perus e humanos, respectivamente, e incluiu todos os transcritos com substituições de nucleotídeos. A segunda classe de transcritos foi caracterizada pela deleção de bases que levaram a um stop códon prematuro e a uma proteína truncada não-funcional. Esses resultados são até o momento, o primeiro relato de sequenciamento do αRYR, região hotspot1 de frangos e podem servir como guia para estudos futuros na tentativa de se encontrar uma solução para os problemas na cadeia de produção de frangos relacionados com as carnes PSE (pálida, flácida e exsudativa).

Samples of Pectoralis major m. were collected, and an RT-PCR analysis of the a-Ryanodine receptor (a RYR) from chicken mRNA hotspot region spanning aminoacid residues 386 to 540, numbered according to the turkey sequence, revealed two classes of transcripts. The sequences of the first class were similar to turkey and human with 97% and 74% of identity, respectively, and included all transcripts with substitutions in the nucleotide sequence. The second class was characterized by the deletion of nucleotides, leading to a premature stop codon and coding for a truncated and nonfunctional protein. These results are to date the first report related to the sequencing of the chicken αRYR hotspot region 1, which will possibility serve as a guide for further studies regarding a solution in the poultry production chain related to the problem of pale, soft and exudative (PSE) meat.

Xylella fastidiosa Wells et al. é uma bactéria gram-negativa, limitada ao xilema de plantas e responsável por doenças de importância econômica em diversas culturas, como a requeima-da-folha ou atrofia-dos-ramos em cafeeiro. É transmitida por insetos sugadores de xilema e quatro espécies de cigarrinhas já foram descritas como transmissoras do patógeno para cafeeiro. O objetivo deste trabalho foi determinar o grau de infectividade natural por X. fastidiosa em cinco espécies de cigarrinhas Cicadellidae potencialmente transmissoras da bactéria para cafeeiro: Acrogonia citrina Marucci & Cavichioli, Bucephalogonia xanthophis (Berg), Dilobopterus costalimai Young, Oncometopia facialis (Signoret) e Sonesimia grossa (Signoret). As coletas foram realizadas em lavouras cafeeiras de cinco municípios das regiões Norte e Noroeste do Paraná, de outubro de 1998 a novembro de 2001. O total de 806 amostras contendo de três a cinco insetos foi examinado para presença de X. fastidiosa utilizando os testes de PCR e nested PCR. Os resultados obtidos revelaram a presença de X. fastidiosa em amostras de todas as cinco espécies de cigarrinhas nas duas regiões cafeeiras. O potencial infectivo natural das amostras foi de 30,4% e variou de 2,2% para O. facialis a 68,8% para A. citrina. As cigarrinhas coletadas na primavera apresentaram tendência para menor infectividade natural de X. fastidiosa quando comparadas com as amostras coletadas nas outras três estações do ano. Os resultados obtidos revelaram o grande potencial de disseminação de X. fastidiosa por insetos vetores em cafeeiros no Paraná.

Xylella fastidiosa Wells et al., a gram-negative and xylem limited bacterium, causes significative economic on several crops, such as the leaf scorch in coffee. It is transmitted by xylem feeding insects and four sharpshooters species have been reported as vectors of X. fastidiosa in coffee. The objective of this study was to determine the natural infectivity of X. fastidiosa in five species of sharpshooters from coffee trees: Acrogonia citrina Marucci & Cavichioli, Bucephalogonia xanthophis (Berg), Dilobopterus costalimai Young, Oncometopia facialis (Signoret) and Sonesimia grossa (Signoret). Samples were collected from coffee plantations in five counties of the North and Northwest regions of the State of Parana, Brazil, from October 1998 through November 2001. A total of 806 samples containing three to five insects were examined for the presence of X. fastidiosa by using PCR and nested PCR tests. X. fastidiosa was present in samples of all five species of sharpshooters collected in the two coffee regions. The average level of natural infectivity potential was 30.4%. However, this natural infectivity ranged from 2.2% for O. facialis to 68.8% for A. citrina. Sharpshooters collected in the spring tended to have lower natural infectivity of X. fastidiosa as compared to those collected in other seasons. The results obtained showed the high potential of dissemination of X. fastidiosa by different insect vectors in coffee trees in Parana.