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低乳糖牛乳粉品质分析及蛋白特性研究
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作者 朱小朋 朱丽 +1 位作者 付尚辰 刘永峰 《食品与发酵工业》 CAS CSCD 北大核心 2024年第13期157-165,共9页
为获得品质优良的低乳糖牛乳粉,该试验以生牛乳为原料,分别使用3种不同乳糖酶水解牛乳,对水解后的牛乳进行喷雾干燥得到了低乳糖牛乳粉-乳糖酶A(low lactose milk powder-enzyme A,LLMP-EA)、低乳糖牛乳粉-乳糖酶B(low lactose milk pow... 为获得品质优良的低乳糖牛乳粉,该试验以生牛乳为原料,分别使用3种不同乳糖酶水解牛乳,对水解后的牛乳进行喷雾干燥得到了低乳糖牛乳粉-乳糖酶A(low lactose milk powder-enzyme A,LLMP-EA)、低乳糖牛乳粉-乳糖酶B(low lactose milk powder-enzyme B,LLMP-EB)、低乳糖牛乳粉-乳糖酶C(low lactose milk powder-enzyme c,LLMP-EC),测定其理化指标和游离巯基等蛋白特性。结果表明,LLMP-EA、LLMP-EB和LLMP-EC的外观及组织状态相近、色泽偏白,LLMP-EA的水分活度比LLMP-EB、LLMP-EC分别低6.29%、4.07%(P<0.05);LLMP-EA的水分含量比LLMP-EB、LLMP-EC分别低6.13%、3.32%(P<0.05);LLMP-EA多分散性指数(polydispersity index,PDI)值为0.13,LLMP-EA、LLMP-EB和LLMP-EC的Zeta电位无显著性差异(P>0.05);通过扫描电镜(scanning electron microscope,SEM)观察发现,LLMP-EA乳粉颗粒较为饱满、表面光滑、有轻微凹陷、颗粒聚集程度较低;LLMP-EA的游离巯基含量比LLMP-EB、LLMP-EC分别低19.90%、12.15%(P<0.05),而LLMP-EA表面疏水性比LLMP-EB低12.29%(P<0.05);LLMP-EA的α-螺旋结构分别比LLMP-EB、LLMP-EC高1.35%、1.94%(P<0.05)。因此,LLMP-EA的水分含量和水分活度低、PDI值仅为0.13,品质最佳;游离巯基含量和溴酚蓝结合量低、α-螺旋含量高,蛋白特性较好。 展开更多
关键词 乳糖乳粉 乳糖 蛋白特性 稳定性 二级结构
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半乳糖基牛血清白蛋白的制备和测定 被引量:3
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作者 贺俊峰 崔光华 +1 位作者 黄伟 孙仁安 《辽宁师范大学学报(自然科学版)》 CAS 2001年第4期389-391,共3页
为了实现肝靶向给药的目的 ,同时避免使用价格昂贵 ,且来源有限的内源性配体 ,我们用还原胺化法合成了半乳糖基牛血清白蛋白 (Galn BSA) .对得到的产物 ,分别用苯酚 硫酸比色法和MADLI TOF质谱法测定了糖化比率 ,在糖化比率较低时 ,两... 为了实现肝靶向给药的目的 ,同时避免使用价格昂贵 ,且来源有限的内源性配体 ,我们用还原胺化法合成了半乳糖基牛血清白蛋白 (Galn BSA) .对得到的产物 ,分别用苯酚 硫酸比色法和MADLI TOF质谱法测定了糖化比率 ,在糖化比率较低时 ,两种方法的结果一致 ,糖化比率较高时 ,苯酚 展开更多
关键词 肝靶向 乳糖血清白蛋白 MADLI-TOF质谱 苯酚-硫酸比色法 制备 测定 制剂 糖化比率
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半乳糖化白蛋白汉防己甲素纳米粒的合成
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作者 余潜 王卓缨 肖大伟 《上海中医药杂志》 2009年第6期80-82,共3页
目的制备半乳糖化白蛋白汉防己甲素纳米粒(Galn-BSA-Tet-NPs),并考察合成半乳糖化白蛋白的最佳条件。方法以乳糖和牛血清白蛋白为原料,采用还原胺化法制备半乳糖化白蛋白(Galn-BSA)。采用苯酚-硫酸比色法测定糖化比率,以糖化比率作为指... 目的制备半乳糖化白蛋白汉防己甲素纳米粒(Galn-BSA-Tet-NPs),并考察合成半乳糖化白蛋白的最佳条件。方法以乳糖和牛血清白蛋白为原料,采用还原胺化法制备半乳糖化白蛋白(Galn-BSA)。采用苯酚-硫酸比色法测定糖化比率,以糖化比率作为指标考察反应的pH、时间、催化物剂量的多个水平,从中选出最优化组合。并采用去溶剂化法制备半乳糖化白蛋白汉防己甲素纳米粒(Galn-BSA-Tet-NPs)。结果制备半乳糖化白蛋白的最佳条件是磷酸缓冲液的pH值为7.4,反应时间为80h,氰基硼氢化钠的催化量为0.8mmol/L;成功合成了半乳糖化白蛋白汉防己甲素纳米粒(Galn-BSA-Tet-NPs)。结论汉防己甲素可以采用去溶剂化法制备成半乳糖化白蛋白纳米粒,此方法可提高汉防己甲素在水相中的浓度,并靶向肝细胞,从而增强汉防己甲素的抗肝纤维化药效。 展开更多
关键词 汉防己甲素 肝靶向 乳糖血清白蛋白 苯酚-硫酸比色法
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再生肝胞液对肝损伤大鼠血清胰岛素及其与肝细胞结合的影响
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作者 哈团柱 徐柯 +1 位作者 陈九莉 张晓先 《南京医学院学报》 CSCD 1989年第4期266-269,共4页
研究了再生肝胞液(RLC)对实验性肝损伤大鼠血清胰岛素、C-肽水平及肝细胞结合A14[^(125)I]、胰岛素的影响;观察了RLC与胰岛素、高血糖合并应用对部分肝切除小鼠残余肝DNA合成的作用。结果表明:(1)氨基半乳糖(GaIN)中毒大鼠血清胰岛素水... 研究了再生肝胞液(RLC)对实验性肝损伤大鼠血清胰岛素、C-肽水平及肝细胞结合A14[^(125)I]、胰岛素的影响;观察了RLC与胰岛素、高血糖合并应用对部分肝切除小鼠残余肝DNA合成的作用。结果表明:(1)氨基半乳糖(GaIN)中毒大鼠血清胰岛素水平降低与胰岛素分泌减少和肝细胞结合增加有关;RLC治疗后血清胰岛素的降低,仅与肝细胞结合增加有关。(2)胰岛素对肝再生的调控作用,在一定范围内,不仅仅取决于它在血液中的水平,而且取决于它与肝细胞结合的数量。 展开更多
关键词 肝再生 细胞提取物 胰岛素 牛乳糖
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The Effect of Culture Condition on Type 5 Capsular Polysaccharide Production of Staphylococcus aureus from Diary Cattle 被引量:13
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作者 杨正涛 张乃生 +2 位作者 刘庆涛 杨琦 尹荣兰 《Agricultural Science & Technology》 CAS 2008年第1期85-88,共4页
[Objective] The effect of different culture conditions on type 5 capsular polysaccharide production of Staphylococcus aureus from diary cattle was studied to provide simple way for CP production and preparation and la... [Objective] The effect of different culture conditions on type 5 capsular polysaccharide production of Staphylococcus aureus from diary cattle was studied to provide simple way for CP production and preparation and laid foundation for carrying out new polysaccharide vaccine research. [Method] Staph-ylococcus aureus was isolated from milk sample of sick dairy cattle and capsular polysaccharide serotypes were identified. Type 5 capsular polysaccharide was cultured on BHI,solid columbia and mod110 culture media. Glucose and lactose were taken as carbon sources for every culture media in solid and liquid state. Therefore 9 different culture conditions were taken to study the effect of culture conditions on capsular polysaccharide production. [Result] Different culture conditions indicated that compared with columbia culture media, BHI culture media could decline capsular polysaccharide production and mod110 culture media could increase capsular polysaccharide production. While for same culture media, solid culture media was better for capsular polysaccharide production,meanwhile,taken lactose as carbon source could increase capsular polysaccharide production. 展开更多
关键词 Staphylococcus aureus Capsular Polysaccharide Culture condition
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Prevalence of lactase persistent/non-persistent genotypes and milk consumption in a young population in north-west Russia 被引量:2
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作者 Yulia Khabarova Suvi Torniainen +3 位作者 Hanna Nurmi Irma Jrvel Mauri Isokoski Kari Mattila 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第15期1849-1853,共5页
AIM: TO estimate the prevalence of the lactase non-persistent genotype (C/C-23910) in a northern Russian population in accordance with ethnicity, and to evaluate self-reported milk consumption depending on lactase ... AIM: TO estimate the prevalence of the lactase non-persistent genotype (C/C-23910) in a northern Russian population in accordance with ethnicity, and to evaluate self-reported milk consumption depending on lactase activity. METHODS: Blood samples for genotyping lactase activity, defining the C/T-13910 variant by polymerase chain reaction, and direct sequencing were taken from 231 medical students of Russian origin aged 17-26 years. We analyzed milk product consumption by questionnaire which was specially designed for the estimation of milk consumption and abdominal complaints. RESULTS: We found that the prevalence of the C/C-13190 genotype in the northern Russian population was 35.6%. The other genotypes nearby C/T-13910 and associated with lactase activity were not present in the study population. The consumption of milk among people with the non-persistent genotype tended to be lower than among the lactose tolerant subjects, but was not statistically significant. CONCLUSION: An investigation of the lactase persistent genotype in a northern Russian population has not been performed before, The genotype did not affect the consumption of milk products in this population which could be explained by low consumption of milk products among the entire study population. 展开更多
关键词 C/C-13910 genotype Hypolactasia Lactasepersistence/non-persistence Lactose malabsorption Milk consumption North-west Russia
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EXPRESSION OF HUMAN α-GALACTOSIDASE AND α1,2-FUCOSYL-TRANSFERASE GENES MODIFIES THE CELL SURFACE GALα1,3GAL ANTIGEN AND CONFERS RESISTANCETO HUMAN SERUM-MEDIATED CYTOLYSIS
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作者 贾延军 任会明 +5 位作者 高新 季守平 杨军 刘泽鹏 李素波 章扬培 《Chinese Medical Sciences Journal》 CAS CSCD 2004年第1期31-37,共7页
Objective To explore the strategies which reduce the amount of xenoantigen Galα1, 3 Gal. Methods Human α-galactosidase gene and α1,2-fucosyltransferase gene were transferred into cul-tured porcine vascular endothel... Objective To explore the strategies which reduce the amount of xenoantigen Galα1, 3 Gal. Methods Human α-galactosidase gene and α1,2-fucosyltransferase gene were transferred into cul-tured porcine vascular endothelial cells PEDSV.15 and human α-galactosidase transgenic mice were produced. The Galα1,3Gal on the cell surface and susceptibility of cells to human antibody-mediated lysis were analyzed. Results Human α-galactosidase gene alone reduced 78% of Galα1,3Gal on PEDSV.15 cell surface while human α-galactosidase combined with α1,2-fucosyltransferase genes removed Galα1,3Gal completely. Decrease of Galα1,3Gal could reduce susceptibility of cells to human antibody-mediated lysis, especially during co-expression of α-galactosidase gene and α1,2-fucosyltransferase gene. RT-PCR indicated positive human α-galactosidase gene expression in all organs of positive human α-galacto-sidase transgenic F1 mice including heart, liver, kidney, lung, and spleen, the amount of Galα1,3Gal antigens on which was reduced largely. 58% of spleen cells from F1 mice were destroyed by comp-lement-mediated lysis compared with 24% of those from normal mice. Conclusions Human α-galactosidase gene and α1,2-fucosyltransferase gene effectively reduce the expression of Galα1,3Gal antigens on endothelial cell surface and confers resistance to human serum-mediated cytolysis. The expression of human α-galactosidase in mice can also eliminate the Galα1,3Gal antigens in most tissues and decrease the susceptibility of spleen cells to human serum-mediated cytolysis. 展开更多
关键词 galactosidase gene hyperacute rejection Galα1 3Gal antigen
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Construction and Expression of β-galactosidase Genetically Engineered Lactococcus lactis 被引量:1
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作者 吕晓英 张朝武 +3 位作者 裴晓方 刘祥 余倩 刘衡川 《Journal of Microbiology and Immunology》 2004年第4期243-249,共7页
Our objective is to solve the lactose malabsorption and intolerance of human beings by combining micro-ecology path with genetic engineering technique. Plasmid pMG36e was used to clone and express a β-galactosidase g... Our objective is to solve the lactose malabsorption and intolerance of human beings by combining micro-ecology path with genetic engineering technique. Plasmid pMG36e was used to clone and express a β-galactosidase gene from L. delbrueckü bulgaricus strain 1.1480 in the Lactococcus lactis subsp. cremoris MG1363 and Lactococcus lactis subsp. lactis IL1403. The recombinant plasmid was preserved and proliferated in Escherichia coli ( E. coli) JM109, and transformed into MG1363 and IL1403 by electroporation. The protein expression was studied. ( 1 ) The bifidobacterium culture medium ( BBL) was suitable for the growth of the strain 1.1480. (2) With 13 amino acids at the N-terminus from the vector, β-gal- actosidase fusion protein (which retained the enzyme activity) could be successfully expressed in E. coli JM109, MG1363 and IL1403, but the expression quantity was larger in the former than in the latter two. (3) The SD sequence designed could be successfully recognized by both the E. coli and the Lactococcus lactis, but the expression level of the non-fusion β-galac- tosidase protein was lower than that of the fusion protein in the same host. The β-galactosidase genetically engineered E. coli JM109 is a useful tool to produce this enzyme in vitro . The signal peptide of the usp45 protein from the Lactococcus lac- tis can be added before the promoter sequence to promote β-galactosidase secretion from Lactococcus lactis . The potential ap- plication of the β-galactosidase genetically engineered MG1363 and IL1403 to cure the lactose malabsorption and lactose in- tolerance in both health food and medicine is promising. 展开更多
关键词 galactosidase Lactic acid bacteria L. delbrueckii bulgaricus ljactococcus lactis Plasmid Genetic engi- neering
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Molecularly defined adult-type hypolactasia among working age people with reference to milk consumption and gastrointestinal symptoms 被引量:1
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作者 Sari R Anthoni Heli A Rasinper +4 位作者 Antti J Kotamies Hanna A Komu Harri K Pihlajamki Kaija-Leena Kolho Irma E Jrvel 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第8期1230-1235,共6页
AIM: To study milk consumption and subjective milk- related symptoms in adults genotyped for adult-type hypolactasia. METHODS: A total of 1900 Finnish adults were genotyped for the C/T-13910 variant of adult-type hypo... AIM: To study milk consumption and subjective milk- related symptoms in adults genotyped for adult-type hypolactasia. METHODS: A total of 1900 Finnish adults were genotyped for the C/T-13910 variant of adult-type hypolactasia and filled in a structured questionnaire concerning milk consumption and gastrointestinal problems. RESULTS: The C/C-13910 genotype of adult-type hypolactasia was present in 18% of the study population. The prevalence of the C/C-13910 genotype was higher among subjects who were undergoing investigations because of abdominal symptoms (24%, P < 0.05). Those with the C/C-13910 genotype drank less milk than subjects with either the C/T-13910 or the T/T-13910 genotype of lactase persistence (18% vs 38%; 18% vs 36%, P < 0.01). Subjects with the C/C-13910 genotype had experienced more gastrointestinal symptoms (84%) during the preceding three-month period than those with the C/T-13910 (79%, P < 0.05) or the T/T-13910 genotype (78 %, P < 0.05). Only 9% (29/338) of the subjects with the C/C-13910 genotype consumed milk and reported no symptoms from it.CONCLUSION: Gastrointestinal symptoms are more common among adults with the C/C-13910 genotype of adult-type hypolactasia than in those with genotypes of lactase persistence. 展开更多
关键词 Lactase persistence Lactose malabsorption C/T-13910 genotype Abdominal symptoms Milk consumption
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Effect of Sugar Beet Top Ensiled with Sugar Cane Bagass in Diet of Lactating Buffaloes
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作者 Ishagh Kord-Nejad Hassan Fazaeli +1 位作者 Kayvan Karkoodi Ahmad Khayyat 《Journal of Agricultural Science and Technology(A)》 2012年第2期278-283,共6页
Sugar beet tops including leaves and crown harvested and chopped into 3-6 cm, mixed with sugar cane pulp and sugar cane molasses (about 5% of the total mass) to provide a mixture contained 30-35 percent dry mater. A... Sugar beet tops including leaves and crown harvested and chopped into 3-6 cm, mixed with sugar cane pulp and sugar cane molasses (about 5% of the total mass) to provide a mixture contained 30-35 percent dry mater. After two months of ensiling, the silage was evaluated and used in the ration of lactating buffaloes. A Latin square experiment in a changeover design, with three periods of time, each with 20 days for adaptation and 10 days for recording data, was conducted in which 15 multiparous lactating buffloes were used in three similar groups, each with five animals. The prepared silage was included in the diet of lactating buffaloes where a control diet (A) was compared with treatment diets contained 25% (B) and 50% (C) silage (DM basis) respectively. Milk yield was recorded, sampled and analysed for fat, protein, solid not-fat and total solids-content. The maximum daily rough milk yield per animal was obtained on diet C while minimum on diet A (P 〈 0.05). Similar trends were observed for 4% fat corrected milk, and 3.5% fat corrected milk that were significantly different between the treatments (P 〈 0.05). The percentage of crude fat and daily fat yield per animal were significantly (P 〈 0.05) higher in treatment C comparing to A and B. An increasingly trend of milk and fat yield was observed when the animals received silage contained diets but statistically it was significant only for the diets contained 50% silage. In addition, the fat percentage was significantly (P 〈 0.05) increased when the buffaloes received diet containing 50% silage. The highest (P 〈 0.05) amount of protein and total solid yield obtained, when the animals received high (50%) silage diet. 展开更多
关键词 Sugar beet top SILAGE milking buffaloes.
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