RESUMO
The mammary gland increases energy requirements during pregnancy and lactation to support epithelial proliferation and milk nutrients synthesis. Lactose, the principal carbohydrate of the milk, is synthetized in the Golgi of mammary epithelial cells by lactose synthase from glucose and UPD galactose. We studied the temporal changes in the expression of GLUT1 and GLUT8 in mammary gland and their association with lactose synthesis and proliferation in BALB/c mice. Six groups were used: virgin, pregnant at 2 and 17 days, lactating at 2 and 10 days, and weaning at 2 days. Temporal expression of GLUT1 and GLUT8 transporters by qPCR, western blot and immunohistochemistry, and its association with lactalbumin, Ki67, and cytokeratin 18 within mammary tissue was studied, along with subcellular localization. GLUT1 and GLUT8 transporters increased their expression during mammary gland progression, reaching 20-fold increasing in GLUT1 mRNA at lactation (p < 0.05) and 2-fold at protein level for GLUT1 and GLUT8 (p < 0.05 and 0.01, respectively). The temporal expression pattern was shared with cytokeratin 18 and Ki67 (p < 0.01). Endogenous GLUT8 partially co-localized with 58 K protein and α-lactalbumin in mammary tissue and with Golgi membrane-associated protein 130 in isolated epithelial cells. The spatial-temporal synchrony between expression of GLUT8/GLUT1 and alveolar cell proliferation, and its localization in cis-Golgi associated to lactose synthase complex, suggest that both transporters are involved in glucose uptake into this organelle, supporting lactose synthesis.
Assuntos
Células Epiteliais/metabolismo , Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Transportador de Glucose Tipo 1/metabolismo , Complexo de Golgi/metabolismo , Glândulas Mamárias Animais/metabolismo , Animais , Células Epiteliais/imunologia , Feminino , Glucose/metabolismo , Proteínas Facilitadoras de Transporte de Glucose/genética , Transportador de Glucose Tipo 1/genética , Queratina-18/metabolismo , Lactalbumina/metabolismo , Lactação , Lactose/biossíntese , Lactose Sintase/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Peptídeos/metabolismo , Gravidez , RNA Mensageiro/metabolismo , Proteína p130 Retinoblastoma-Like/metabolismo , Fatores de Tempo , DesmameRESUMO
We investigated the kinetics of whey bioconversion into ethanol by Kluyveromyces marxianus in continuous bioreactors using the "accelerostat technique" (A-stat). Cultivations using free and Ca-alginate immobilized cells were evaluated using two different acceleration rates (a). The kinetic profiles of these systems were modeled using four different unstructured models, differing in the expressions for the specific growth (µ) and substrate consumption rates (r s), taking into account substrate limitation and product inhibition. Experimental data showed that the dilution rate (D) directly affected cell physiology and metabolism. The specific growth rate followed the dilution rate (µ≈D) for the lowest acceleration rate (a = 0.0015 h(-2)), condition in which the highest ethanol yield (0.52 g g(-1)) was obtained. The highest acceleration rate (a = 0.00667 h(-2)) led to a lower ethanol yield (0.40 g g(-1)) in the system where free cells were used, whereas with immobilized cells ethanol yields increased by 23 % (0.49 g g(-1)). Among the evaluated models, Monod and Levenspiel combined with Ghose and Tyagi models were found to be more appropriate for describing the kinetics of whey bioconversion into ethanol. These results may be useful in scaling up the process for ethanol production from whey.
Assuntos
Etanol/metabolismo , Kluyveromyces/metabolismo , Soro do Leite/metabolismo , Reatores Biológicos , Células Imobilizadas/metabolismo , Meios de Cultura , Cinética , Kluyveromyces/citologia , Lactose/biossínteseRESUMO
The objective of this research was evaluating the influence of lactation stage and the time interval between milkings on milk ingredients and the production of goats in the semi-arid region of Paraiba. It was used 28 animals of Anglo Nubian breed distributed in a completely randomized design in a factorial arrangement of type 3 x 2, three lactation stages and two milking shifts. Analysis of variance revealed no effect (P>0.05) were lactating for fat, protein and total solids. However, there was significant difference (P <0.05) for lactose and milk production within the lactation phases and interval between milkings. For acidity and density, there was no effect (P> 0.05) from lactating, but significant effect (P< 0.05) from the milking turn. There was negative correlation between the shift milking for milk production, acidity, lactose, density, protein and fat. With respect to lactation stage negative correlation was observed for milk production and lactose and positive correlation for acidity and protein. The goat milk composition is influenced by the lactation stage and the interval between milkings. Equal time interval between milkings favors the milk production with a more uniform composition. (AU)
Objetivou-se com esse trabalho avaliar a influência da fase de lactação e do intervalo de tempo entre ordenhas sobre os constituintes e a produção de leite de cabras no semiárido da Paraíba. Foram utilizadas 28 animais da raçaAnglo Nubiana distribuídos em um delineamento inteiramente casualizado em arranjo fatorial do tipo 3 x 2, três fases de lactação e dois turnos de ordenha. A análise de variância não revelou efeito (P>0,05) de fase de lactaçãopara proteína, gordura e sólidos totais. Contudo, houve diferença significativa (P<0,05) para lactose e produção de leite dentro das fases de lactação e intervalo entre ordenhas. Para acidez e densidade não houve efeito (P>0,05) de fase delactação, mas houve efeito (P<0,05) do turno da ordenha. Houve correlação negativa entre o turno da ordenha para produção de leite, acidez, lactose, densidade, proteína e gordura. Com relação à fase de lactação observou-secorrelação negativa para produção de leite e lactose e correlação positiva para acidez e proteína. A composição do leite de cabra sofre influência da fase de lactação e do intervalo entre ordenhas. Intervalo de tempo igual entre asordenhas favorece a produção de um leite com uma composição mais uniforme.(AU)
Assuntos
Animais , Feminino , Lactente , Cabras , Leite/química , Lactose/biossíntese , Acidez/análise , CenchrusRESUMO
The objective of this research was evaluating the influence of lactation stage and the time interval between milkings on milk ingredients and the production of goats in the semi-arid region of Paraiba. It was used 28 animals of Anglo Nubian breed distributed in a completely randomized design in a factorial arrangement of type 3 x 2, three lactation stages and two milking shifts. Analysis of variance revealed no effect (P>0.05) were lactating for fat, protein and total solids. However, there was significant difference (P 0.05) from lactating, but significant effect (P< 0.05) from the milking turn. There was negative correlation between the shift milking for milk production, acidity, lactose, density, protein and fat. With respect to lactation stage negative correlation was observed for milk production and lactose and positive correlation for acidity and protein. The goat milk composition is influenced by the lactation stage and the interval between milkings. Equal time interval between milkings favors the milk production with a more uniform composition.
Objetivou-se com esse trabalho avaliar a influência da fase de lactação e do intervalo de tempo entre ordenhas sobre os constituintes e a produção de leite de cabras no semiárido da Paraíba. Foram utilizadas 28 animais da raçaAnglo Nubiana distribuídos em um delineamento inteiramente casualizado em arranjo fatorial do tipo 3 x 2, três fases de lactação e dois turnos de ordenha. A análise de variância não revelou efeito (P>0,05) de fase de lactaçãopara proteína, gordura e sólidos totais. Contudo, houve diferença significativa (P0,05) de fase delactação, mas houve efeito (P<0,05) do turno da ordenha. Houve correlação negativa entre o turno da ordenha para produção de leite, acidez, lactose, densidade, proteína e gordura. Com relação à fase de lactação observou-secorrelação negativa para produção de leite e lactose e correlação positiva para acidez e proteína. A composição do leite de cabra sofre influência da fase de lactação e do intervalo entre ordenhas. Intervalo de tempo igual entre asordenhas favorece a produção de um leite com uma composição mais uniforme.
Assuntos
Feminino , Animais , Lactente , Cabras , Leite/química , Acidez/análise , Cenchrus , Lactose/biossínteseRESUMO
Um dos maiores desafios da biotecnologia é a reduçäo da demanda bioquímica de oxigênio do soro de leite com concomitante produçäo de um combustível líquido. Utilizamos, para este fim, Escherichia coli ATCC 11775 contendo o plasmidio pLOI 297 que codifica as enzimas etanologênicas de Zymomonas mobilis capazes de converter lactose em etanol. No processo fermentativo, os seguintes parâmetros foram estudados: preparo do inóculo, concentraçäo de lactose e adiçäo de nutrientes ao soro de leite. As melhores condiçöes em relaçäo em ao inóculo foram: crescimento em seis horas com agitaçäo em meio Luria. O inóculo foi de 10 por cento do volume de fermentaçäo. Em relaçäo à concentraçäo de lactose, detectamos que acima de 80g/l, há um resíduo de galactose no meio de fermentaçäo. A quantidade de etanol produzida a partir de soro de leite suplementado com triptona foi de 38g/l com eficiência de 85 p/cento
Assuntos
Etanol , Escherichia coli/metabolismo , Lactose/biossínteseRESUMO
The cheese whey is one of the most important effluents which is being disposed off in our area. That is why the study for optimizing conditions in the process of recovering whey to produce protein biomass in a batch fermenter was undertaken. A yeast strain (Kluyveromyces marxianus var. lactis) was propagated on a medium based on whey from cheese making plants, the following conditions for cell development being optimized: temperature, pH and initial concentration of lactose. A methodology based on performing several tests ordered according to a "Latin Squares" structure was proposed; this enables the simultaneous study of three variables with a small number of experiences. Such experiences were performed in a cylindrical (air lift type) glass fermenter, obtaining a maximum yield (4.78 g/l by dry weight) when working with an initial lactose concentration equal to 4.8%. For all temperatures (27, 30 and 35 degrees C) and pH (3, 4 and 5) employed, an increase in the cell number occurred with the initial lactose concentration increasing from 2% to 4.8% (Table 2). It is preferable to work at 27 degrees C and pH 4 (since these conditions minimize the bacterial contamination) and with a lactose concentration equal to 4.8%, i.e. the concentration in the residual cheese whey. Thus, an optimum yield in protein biomass is obtained, enabling a good utilization of this effluent, and also diminishing its initial BOD from 60,000 to 15,000 ppm.