Action of microbial transglutaminase (MTGase) in the modification of food proteins: a review.

Microbial transglutaminase (MTGase) is an enzyme of the class of transferases widely known to modify protein functional properties in food systems. The main mechanisms of action involved are polymerisations, which result in changes in the molecule's hydrophobicity. Among the functional properties, MTGase affects solubility and hence gelation, emulsification, foaming, viscosity and water-holding capacity, which all depend on protein solubility. Although the enzyme's benefits for protein functionality in a variety of food systems are widely reported in the literature, few studies have focussed on its mechanisms. The purpose of this review is therefore to investigate the mechanisms of action of MTGase and consider its influence on the functional properties with different protein substrates. Understanding these mechanisms is the first step in the development and application, in food production, of new and better functional properties with improved and/or innovative characteristics that can satisfy consumer expectations.

[Effects of androgenic anabolic steroids on the uterus and reproductive parameters of adult female rats]. / Efeitos dos esteroides anabólicos androgênicos sobre o útero e parâmetros reprodutivos de ratas adultas.

PURPOSE: to evaluate the effects of the administration of two synthetic steroids in the uterus morphology and in the reproductive parameters of adult female rats. METHODS: divided into four experimental groups: control (C; physiological solution); treated with nandrolone decanoate (DN; 7.5 mg/kg of body weight); with a testosterone esters compound (T; 7.5 mg/kg); and simultaneously with DN and T (7.5 mg/kg of each steroid), in a single intraperitoneal weekly dose, for eight weeks. Five females of each group were sacrificed and the uterine horns were collected, weighted and prepared for histological and morphometrical evaluation. The remaining rats were mated with normal male rats for reproductive parameters evaluation, composing the groups treated during the pre-gestational period. Another group of 20 female rats were treated during the gestational period (7th-14th days). For data analysis, the Kruskal-Wallis non-parametric variance analysis was used, followed by the test of Dunn or of Student-Newman-Keus (5% significance level). RESULTS: there was a significant body weight increase in the androgenized females (ND: 305+/-50; T: 280+/-35; ND+T: 275+/-30 versus C: 255+/-22 g; p<0.05). Uterine weight was not affected by the steroidal treatment (ND: 0.6+/-0.2; T: 0.4+/-0.04; ND+T: 0.7+/-0.1 versus C: 0.4+/-0.09 g). All the androgenized females presented estral acyclicity and endometrium characterized by papilliferous luminal lining, oedematous stroma with hemorrhagic areas and secretory activity. There were changes in the morphometrical thickness parameters of the luminal epithelium, myometrium and perimetrium in the androgenized groups. None of the female rats got pregnant when treated with steroids in the pre-gestational period and the treatment during organogenesis affected negatively the reproductive parameters. CONCLUSIONS: steroidal agents alter the uterine structure and impair fertility and gestational outcome in female rats.

Efeitos dos esteroides anabólicos androgênicos sobre o útero e parâmetros reprodutivos de ratas adultas / Effects of androgenic anabolic steroids on the uterus and reproductive parameters of adult female rats

OBJETIVO: avaliar os efeitos da administração de dois esteroides sintéticos sobre a morfologia do útero e parâmetros reprodutivos de ratas adultas. MÉTODOS: quarenta ratas foram aleatoriamente distribuídas nos grupos experimentais: controle (C; solução fisiológica); tratados com decanoato de nandrolona (DN; 7,5 mg/kg de peso corpóreo); composto de ésteres de testosterona (T; 7,5 mg/kg de peso corpóreo); e, simultaneamente, com DN e T (7,5 mg/kg de peso corpóreo de cada esteroide), em uma única dose/semana, intraperitoneal, durante oito semanas. Cinco fêmeas de cada grupo foram sacrificadas e os cornos uterinos foram coletados, pesados e preparados para avaliação histológica e morfométrica. As ratas restantes foram acasaladas com machos normais para avaliação dos parâmetros reprodutivos, constituindo os grupos tratados durante o período pré-gestacional. Outro grupo de 20 ratas recebeu os tratamentos durante o período gestacional (7º-14º dias). Foi aplicada a análise de variância não paramétrica de Kruskal-Wallis, complementada com o teste de Dunn ou de Student-Newman-Kleus para análise dos dados (5 por cento de significância). RESULTADOS: houve aumento significativo no peso corpóreo das fêmeas androgenizadas (DN: 305±50; T: 280±35; DN+T: 275±30 versus C: 255±22 g) (p<0,05). O peso uterino não foi afetado pelos tratamentos esteroidais (DN: 0,6±0,2; T: 0,4±0,04; DN+T: 0,7±0,1 versus C: 0,4±0,09 g). Todas as fêmeas androgenizadas apresentaram aciclicidade estral e endométrio caracterizado pelo revestimento luminal papilífero, estroma edematoso com áreas hemorrágicas e atividade secretora. Houve alterações nos parâmetros morfométricos de espessura do epitélio luminal, miométrio e perimétrio, em função do grupo androgenizado. Nenhuma rata exibiu prenhez quando tratada com os esteroides no período pré-gestacional, e o tratamento durante a organogênese afetou negativamente os parâmetros reprodutivos. CONCLUSÕES: os agentes esteroidais alteram ...

PURPOSE: to evaluate the effects of the administration of two synthetic steroids in the uterus morphology and in the reproductive parameters of adult female rats. METHODS: divided into four experimental groups: control (C; physiological solution); treated with nandrolone decanoate (DN; 7.5 mg/kg of body weight); with a testosterone esters compound (T; 7.5 mg/kg); and simultaneously with DN and T (7.5 mg/kg of each steroid), in a single intraperitoneal weekly dose, for eight weeks. Five females of each group were sacrificed and the uterine horns were collected, weighted and prepared for histological and morphometrical evaluation. The remaining rats were mated with normal male rats for reproductive parameters evaluation, composing the groups treated during the pre-gestational period. Another group of 20 female rats were treated during the gestational period (7th-14th days). For data analysis, the Kruskal-Wallis non-parametric variance analysis was used, followed by the test of Dunn or of Student-Newman-Keus (5 percent significance level). RESULTS: there was a significant body weight increase in the androgenized females (ND: 305±50; T: 280±35; ND+T: 275±30 versus C: 255±22 g; p<0.05). Uterine weight was not affected by the steroidal treatment (ND: 0.6±0.2; T: 0.4±0.04; ND+T: 0.7±0.1 versus C: 0.4±0.09 g). All the androgenized females presented estral acyclicity and endometrium characterized by papilliferous luminal lining, oedematous stroma with hemorrhagic areas and secretory activity. There were changes in the morphometrical thickness parameters of the luminal epithelium, myometrium and perimetrium in the androgenized groups. None of the female rats got pregnant when treated with steroids in the pre-gestational period and the treatment during organogenesis affected negatively the reproductive parameters. CONCLUSIONS: steroidal agents alter the uterine structure and impair fertility and gestational outcome in female rats.