Gracilaria tenuistipitata var Liui were mono cultivated and co cultivated with Pinctada martensii under high (33) and low (21) salinity conditions in laboratory. The daily growth rate of the alga was determined. Tissu...Gracilaria tenuistipitata var Liui were mono cultivated and co cultivated with Pinctada martensii under high (33) and low (21) salinity conditions in laboratory. The daily growth rate of the alga was determined. Tissue carbon and nitrogen contents, the yield and fractional composition of agar were analyzed. Results showed that: 1. Gracilaria grew better under low salinity conditions, the daily growth rate was twice that under high salinity conditions. Co cultivated algae grew faster than mono cultivated algae under low salinity conditions, the daily growth rate was about 37.6% higher. 2. Compared with mono cultivated algae, tissue nitrogen contents of co cultivated algae were higher, while the C:N ratios were much lower. 3. The agar yields of co cultivated algae were much lower than those of mono cultivated algae. Agar yield was found to be negatively correlated to the tissue nitrogen contents, and positively correlated to the C:N ratios. 4. The highest fractional yields obtained from co cultivated algae were extracted with 40% ethanol, while from mono cultivated algae, the highest fractional yields obtained were extracted with distilled water at room temperature.展开更多
According literature, the induction of Yarrowia lipolytica alkaline protease promoter （PXPR2） is efficient in pH 〉 6.0 and with high peptone dose. To establish optimal pH and peptone concentration for induction of ...According literature, the induction of Yarrowia lipolytica alkaline protease promoter （PXPR2） is efficient in pH 〉 6.0 and with high peptone dose. To establish optimal pH and peptone concentration for induction of invertase gene （suc2 of Saccharomyces cerevisaie） under PXPR2 in new Y. lipolytica A-101 invertase positive （Suc＋） transformants their growth on Bioscreen C was analyzed. Minimal mineral medium with thiamine （MMT） and sucrose （1%）, adjusted to pH from 5.8 to 7.6 and supplemented by 0-0.1% of peptone was used. Biomass （OD）, maximal specific growth rate （μmax） and consumed sucrose were measured. Maximal yeasts growth, resulting from the optimal PXPR2 induction, was observed at pH 7.2 and with very low peptone doses （0.0025% and 0.01%）. For five clones （A-101 1356-5; A-101 B54-6; A-101 B57-4; A-101 A18 and W29 ura3-302） only 0.005% of peptone was needed. Amount of hydrolyzed sucrose varied from 24% to 83% and μmax from 0.06 to 0.28 hl. Suc^＋ clones differ in growth parameters, so the site of yeast cassette integration into genome influences expression level of suc2 under PXPR2. Designing large scale processes with Y. lipolytica Suc^＋ clones peptone concentration has to be 100 times smaller than recommended so far.展开更多
Organic biomass is an attractive feedstock for second generation alcohol production. Wild-type strains of the genus Candida showed capabilities different to produce alcohol fermenting a carbohydrates mixture （synthet...Organic biomass is an attractive feedstock for second generation alcohol production. Wild-type strains of the genus Candida showed capabilities different to produce alcohol fermenting a carbohydrates mixture （synthetic medium）, individually and in co-culture. Therefore, the main objective of this work was to evaluate the capability of Candida wild-type strains isolated from termite gut and rumen liquid, to ferment the most commonly carbohydrates presented in citrus residues, individually and in co-culture to alcohol production. C Tropicalis （LR4） presented higher percentage of carbohydrate consumption （74.20% ± 4.60%）, alcohol production （44.53 ± 0.01 gLl） and maximal alcohol productivity （6.40 ± 0.01 gL-l day） than C Glabrata （T1）. Co-culture schemas, CC1 （LR4： 60%; TI： 40%） and CC3 （first LR4 alone and 2 days later T1） presented the highest alcohol production （45.20 ± 1.30 gL-1 and 46.80 ± 2.60 gL-1, respectively）. Maximal alcohol productivity was obtained with CC2 （LR4： 80%; TI： 20%） and CC3 schemas, 7.70 ± 0.29 gL-1 day and 7.80 ± 0.44 gL-l day, respectively. The results suggest the usefulness of these wild-type strains in co-culture as an alternative to alcohol production from carbohydrates mixtures at concentrations commonly found in citrus waste.展开更多
Accompanying the beneficial improvement in litter size from genetic selection for high-prolificacy sows, within-litter variation in birth weight has increased with detrimental effects on post-natal growth and survival...Accompanying the beneficial improvement in litter size from genetic selection for high-prolificacy sows, within-litter variation in birth weight has increased with detrimental effects on post-natal growth and survival due to an increase in the proportion of piglets with low birth-weight. Causes of within-litter variation in birth weight include breed characteristics that affect uterine space, ovulation rate, degree of maturation of oocytes, duration of time required for ovulation, interval between ovulation and fertilization, uterine capacity for implantation and placentation, size and efficiency of placental transport of nutrients, communication between conceptus/fetus and maternal systems, as well as nutritional status and environmental influences during gestation. Because these factors contribute to within-litter variation in birth weight, nutritional status of the sow to improve fetal-placental development must focus on the following three important stages in the reproductive cycle： pre-mating or weaning to estrus, early gestation and late gestation. The goal is to increase the homogeneity of development of oocytes and conceptuses, decrease variations in conceptus development during implantation and placentation, and improve birth weights of newborn piglets. Though some progress has been made in nutritional regulation of within-litter variation in the birth weight of piglets, additional studies, with a focus on and insights into molecular mechanisms of reproductive physiology from the aspects of maternal growth and offspring development, as well as their regulation by nutrients provided to the sow, are urgently needed.展开更多
文摘Gracilaria tenuistipitata var Liui were mono cultivated and co cultivated with Pinctada martensii under high (33) and low (21) salinity conditions in laboratory. The daily growth rate of the alga was determined. Tissue carbon and nitrogen contents, the yield and fractional composition of agar were analyzed. Results showed that: 1. Gracilaria grew better under low salinity conditions, the daily growth rate was twice that under high salinity conditions. Co cultivated algae grew faster than mono cultivated algae under low salinity conditions, the daily growth rate was about 37.6% higher. 2. Compared with mono cultivated algae, tissue nitrogen contents of co cultivated algae were higher, while the C:N ratios were much lower. 3. The agar yields of co cultivated algae were much lower than those of mono cultivated algae. Agar yield was found to be negatively correlated to the tissue nitrogen contents, and positively correlated to the C:N ratios. 4. The highest fractional yields obtained from co cultivated algae were extracted with 40% ethanol, while from mono cultivated algae, the highest fractional yields obtained were extracted with distilled water at room temperature.
文摘According literature, the induction of Yarrowia lipolytica alkaline protease promoter （PXPR2） is efficient in pH 〉 6.0 and with high peptone dose. To establish optimal pH and peptone concentration for induction of invertase gene （suc2 of Saccharomyces cerevisaie） under PXPR2 in new Y. lipolytica A-101 invertase positive （Suc＋） transformants their growth on Bioscreen C was analyzed. Minimal mineral medium with thiamine （MMT） and sucrose （1%）, adjusted to pH from 5.8 to 7.6 and supplemented by 0-0.1% of peptone was used. Biomass （OD）, maximal specific growth rate （μmax） and consumed sucrose were measured. Maximal yeasts growth, resulting from the optimal PXPR2 induction, was observed at pH 7.2 and with very low peptone doses （0.0025% and 0.01%）. For five clones （A-101 1356-5; A-101 B54-6; A-101 B57-4; A-101 A18 and W29 ura3-302） only 0.005% of peptone was needed. Amount of hydrolyzed sucrose varied from 24% to 83% and μmax from 0.06 to 0.28 hl. Suc^＋ clones differ in growth parameters, so the site of yeast cassette integration into genome influences expression level of suc2 under PXPR2. Designing large scale processes with Y. lipolytica Suc^＋ clones peptone concentration has to be 100 times smaller than recommended so far.
文摘Organic biomass is an attractive feedstock for second generation alcohol production. Wild-type strains of the genus Candida showed capabilities different to produce alcohol fermenting a carbohydrates mixture （synthetic medium）, individually and in co-culture. Therefore, the main objective of this work was to evaluate the capability of Candida wild-type strains isolated from termite gut and rumen liquid, to ferment the most commonly carbohydrates presented in citrus residues, individually and in co-culture to alcohol production. C Tropicalis （LR4） presented higher percentage of carbohydrate consumption （74.20% ± 4.60%）, alcohol production （44.53 ± 0.01 gLl） and maximal alcohol productivity （6.40 ± 0.01 gL-l day） than C Glabrata （T1）. Co-culture schemas, CC1 （LR4： 60%; TI： 40%） and CC3 （first LR4 alone and 2 days later T1） presented the highest alcohol production （45.20 ± 1.30 gL-1 and 46.80 ± 2.60 gL-1, respectively）. Maximal alcohol productivity was obtained with CC2 （LR4： 80%; TI： 20%） and CC3 schemas, 7.70 ± 0.29 gL-1 day and 7.80 ± 0.44 gL-l day, respectively. The results suggest the usefulness of these wild-type strains in co-culture as an alternative to alcohol production from carbohydrates mixtures at concentrations commonly found in citrus waste.
基金Project supported by the National Basic Research Program(973)of China(No.2012CB124703)the National Natural Science Foundation of China(Nos.31129006,31272449,and 31422052)
文摘Accompanying the beneficial improvement in litter size from genetic selection for high-prolificacy sows, within-litter variation in birth weight has increased with detrimental effects on post-natal growth and survival due to an increase in the proportion of piglets with low birth-weight. Causes of within-litter variation in birth weight include breed characteristics that affect uterine space, ovulation rate, degree of maturation of oocytes, duration of time required for ovulation, interval between ovulation and fertilization, uterine capacity for implantation and placentation, size and efficiency of placental transport of nutrients, communication between conceptus/fetus and maternal systems, as well as nutritional status and environmental influences during gestation. Because these factors contribute to within-litter variation in birth weight, nutritional status of the sow to improve fetal-placental development must focus on the following three important stages in the reproductive cycle： pre-mating or weaning to estrus, early gestation and late gestation. The goal is to increase the homogeneity of development of oocytes and conceptuses, decrease variations in conceptus development during implantation and placentation, and improve birth weights of newborn piglets. Though some progress has been made in nutritional regulation of within-litter variation in the birth weight of piglets, additional studies, with a focus on and insights into molecular mechanisms of reproductive physiology from the aspects of maternal growth and offspring development, as well as their regulation by nutrients provided to the sow, are urgently needed.
