共查询到19条相似文献,搜索用时 187 毫秒
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用200~300nm的波长范围对富铬酵母及普通酵母的溶液进行紫外扫描,发现在λ_(260nm)处有一特征紫外吸收峰,富铬酵母细胞的铬含量与其吸收峰的光密度呈线性关系;在不同的温度和pH值条件下,通过紫外吸收峰的测定,富铬酵母溶液在酸性条件下稳定,在碱性条件下不稳定。溶液的λ_(260nm)紫外吸收峰随着温度的上升而升高。从氨基酸含量分析结果看,富铬酵母的谷氨酸、甘氨酸、组氨酸、丙氨酸和赖氨酸含量高于普通酵母,但其他氨基酸含量比普通酵母低。 相似文献
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富硒生物样品中硒的价态和形态分析 总被引:9,自引:0,他引:9
本文利用2,3—二氨基萘(DAN)荧光法测定了富硒玉米粉、硒酵母蛋白等样品中四价硒、六价硒、有机硒含量及总硒量。进一步验证了差减法测定不同价态硒含量的实验方法 相似文献
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铬是人体和动物的必需微量元素。其主要生物效应是调节体内糖代谢,可作为胰岛素的加强剂起作用,促进胰岛素与受体反应,降低体内血糖水平。糖尿病及年龄的增长均会造成血清中铬水平的降低.食物中的铝含量往往不能满足人体在疾病及特殊生理状态下的需要。补充铬可以预防和治疗糖尿病及其它疾病.国内外的研究表明,用富铬酵母补铬是一种有效途径,酵母中3价有机钻的生物活性较无机钻大,容易被机体吸收,同时酵母本身的生物活性物质对生物体也有保健作用.因此富铬酵母的研究具有重要理论意义和应用价值.我们进行了抗铬酵母菌的筛选研究… 相似文献
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实验旨在研究饲料中不同类型和水平的硒源对杂交鲟(Acipenser baerii♂×Acipenser schrenckii♀)幼鱼生长、抗氧化能力及组织硒含量的影响。不同类型的硒源为亚硒酸钠、酵母硒和富硒螺旋藻,添加水平为0、0.4和1.2 mg/kg,制作对照饲料(C)、亚硒酸钠添加饲料(S1和S2)、酵母硒添加饲料(Y1和Y2)和富硒螺旋藻添加饲料(P1和P2)。使用实验饲料饲喂初始体重为(7.82±0.12) g的杂交鲟幼鱼,养殖62d。结果表明,不同硒源和硒水平对杂交鲟幼鱼的特定生长率和饲料效率无显著影响(P>0.05)。高水平亚硒酸钠显著提高了全鱼和肝脏硒含量(P<0.05),但对肌肉和脊椎骨硒含量无显著影响(P>0.05)。高水平酵母硒和富硒藻螺旋添加组杂交鲟幼鱼的全鱼、肝脏、肌肉及脊椎骨硒含量均显著高于对照组(P<0.05)。酵母硒添加组的血浆总蛋白(TP)和总胆固醇(TC)含量均显著高于对照组(P<0.05)。同时,高水平硒添加组杂交鲟幼鱼的血浆谷胱甘肽过氧化物酶(GSH-Px)活性显著高于对照组和低水平硒添加组(P<0.05)。亚... 相似文献
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<正> (还原型)谷胱甘肽(GSH)是酵母细胞中含量很高的一种生物化学活性物质,具有广泛的用途。用鲜酵母(或活性干酵母)作原料在实验制备(还原型)谷胱甘肽结晶成功的基础上,我们应用了酵母生产车间的一般条件,进行了投料量100公斤压榨鲜酵母的中间试验性生产GSH的研究,试验结果基本上和实验室研究结果相符,总收率达:32.9%,如再作改进,收率还可提高。 相似文献
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Ding WJ Qian QF Hou XL Feng WY Chen CY Chai ZF Zhang BR Wang K 《Biological trace element research》2002,88(2):193-199
The purpose of this study was to assess the chromium (Cr) distribution in chromium-rich brewer’s yeast cell. The chromium
concentrations in the cell wall and protoplast fractions of the chromium-rich yeast were determined by neutron activation
analysis (NAA). Moreover, the combined state of chromium and amino acid content in the Cr-rich brewer’s yeasts was analyzed
and measured. The experimental results indicate that the introduction of water-soluble chromium (III) salt as a component
of the culture medium for yeasts results in a substantial amount of chromium absorbed through the cell wall by the yeast,
among which 80.9% are accumulated in the protoplast. It implies that, under optimal conditions, yeasts are capable of accumulating
large amounts of chromium and incorporating chromium into organic compounds. 相似文献
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Monique Simonoff Dennis Shapcott Said Alameddine Marie Thèrèse Sutter-Dub Gabriel Simonoff 《Biological trace element research》1992,32(1-3):25-38
A new dietary factor, the glucose tolerance factor (GTF), was reported in 1957 that improved impaired glucose tolerance in
rats. Most studies on GTF have used brewer's yeast as the starting material, and it has been postulated that the active material
is a low-mol wt organic complex containing Cr3+.
It seemed thus important to isolate an active GTF from chromium-rich yeast (228 ppm Cr) obtained by incubation with chromium
and to compare each fraction with corresponding ones from untreated yeast (0.48 ppm Cr). We developed an isolation and purification
procedure by fractionation of yeast extract on an anion and cation exchange resin, and tested the GTF activity (glucose oxidation)
on rat adipocytes. PIXE (proton-induced X-ray emission) was used to measure the chromium content of the individual fraction.
Individual fractions with GTF activity did not differ between Cr-rich and Cr-deficient yeast, and there was no relationship
between Cr content and GTF activity. This does not support the hypothesis that chromium is an obligatory constituent of the
GTF, assuming that GTF is a unique substance. 相似文献
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Jose Francisco Xavier da Rocha Adelina Rodrigues Aires Matheus Augusto Gonçalves Nunes Erico Marlon Moraes Flores Gilberto Vilmar Kozloski Agueda Castagna de Vargas Luana D’Avila Farias Marcelo da Silva Cecim Marta Lizandra do Rego Leal 《Biological trace element research》2013,156(1-3):130-133
The aim of the present study was to evaluate the metabolism of organic chromium and its effect on digestibility and intake of lambs. Four 4-month-old male lambs, each weighing 28 kg, were used. The animals were kept in metabolic cages for a period of 20 days (15 days of adaptation and 5 days of experimentation), in two experimental phases, with inverted treatments. Organic chromium was administered by intraruminal infusion of 1 mg of chromium-rich yeast (Saccharomyces cerevisiae) throughout the adaptive and experimental period. The dry material rates of the diet and feces of the animals were evaluated to estimate consumption, digestibility, and fecal production. During the experimental period, blood, feces, and urine were collected every 24 h to determine chromium levels. There was no significant difference in the excretion of chromium in the urine, and no mineral remnants were detected in the blood. Excretion was generally fecal. There was greater excretion of chromium in the feces of lambs in the treated group on day 0 and day 3, compared with the control group. The use of organic chromium promoted an increase in the consumption of dry material in the treated animals only at day 0 (P?<?0.05). The production of fecal dry matter was greater among the treated lambs than among the animals of the control group on day 1, day 2, day 3, and day 4 (P?<?0.05). The results obtained showed that organic chromium associated with live yeasts is not absorbed by the body and do not affect the intake time in the dose used. 相似文献
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The enantioselectivity of the enzymes responsible for reduction of prochiral compound 3-phenylthiopropan-2-one was dependent on the concentration of yeast extract and glucose in the growth medium. Low concentrations of yeast extract (0.1-0.9% w/v) favored the formation of S-enantiomer (62% ee at 0.1% w/v yeast extract) of 3-phenylthiopropan-2-ol. However, R-enantiomer of the reduced product was formed when MSM was supplemented with yeast extract at a concentration of 1% (w/v) or more with a maximum ee of 85% at 2.0% (w/v) yeast extract supplement in the growth medium. 相似文献
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Patel AV Jakobs-Schönwandt D Rose T Vorlop KD 《Applied microbiology and biotechnology》2011,89(6):1751-1760
In this work, fermentation and formulation aspects of the nematophagous fungus Hirsutella rhossiliensis BBA were investigated. When incubated in 2% (w/w) glucose and 0.5% (w/w) yeast extract medium in a 1-L Erlenmeyer flask without
baffles, heavy pellet formation was observed. Only 40% of the mycelium had a size less than 500 μm. When a flask with three
baffles was used, the portion of mycelium <500 μm rose to 95%. In the next step, the influence of aeration rate and stirrer
speed on production of finely dispersed mycelium in a stirred tank reactor was investigated. The best fermentation results
were obtained at 0.4 vvm and 400 rpm stirrer speed with 90% mycelium <500 μm and 5 g/L biomass. Then, mycelium was microencapsulated
in hollow beads based on sulfoethylcellulose (SEC). Experiments on the capsule nutrient reservoir showed that 15% (w/w) corn
gluten and 0.5% (w/w) yeast extract could be replaced with 3% (w/w) autoclaved baker's yeast which was never used as capsule
additive before. Radial growth of mycelium out of dried hollow beads containing 1% (w/w) biomass and 3% (w/w) baker's yeast
was faster than for alginate beads containing equivalent amounts of biomass and yeast indicating a higher bio-control potential. 相似文献
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Dietary organic chromium supplementation and its effect on the immune response of rainbow trout (Oncorhynchus mykiss) 总被引:5,自引:0,他引:5
Gatta PP Thompson KD Smullen R Piva A Test S Adams A 《Fish & shellfish immunology》2001,11(5):371-382
Recently, there has been an increasing interest in the potential effect of dietary chromium on the health of fish, particularly with respect to their metabolism and growth. Information as to the role of this mineral on their immune response, is limited however, so the aim of this study was to assess the effects of dietary chromium yeast supplementation on the immune response of rainbow trout (Oncorhynchus mykiss). Juvenile rainbow trout (56 g average weight) were fed three semipurified diets containing different levels of chromium (1540, 2340 and 4110 ppb), obtained by supplementing a basal diet with 800 or 2570 ppb chromium yeast, for 6 weeks. After this, time differences in their immune response were examined. A positive influence was observed on serum lysozyme activity at this time in fish maintained on the high chromium diet. The respiratory burst of head-kidney macrophages was also examined, and statistical differences were found in the level of respiratory burst elicited by macrophages from both groups of fish fed supplemented chromium after 3 and 6 weeks of feeding (absorbance at 3 weeks: 0.118, 0.166. 0.151 and 6 weeks 0.114, 0.168, 0.151 for the 1540, 2340 and 4110 ppb groups). Macrophages of fish receiving diets supplemented with chromium also had a greater ability to phagocytose yeast after 6 weeks than the control fish (40.5, 48 and 48.5% macrophages phagocytic in the 1540, 2340 and 4110 ppb groups, respectively). The results of the study show that chromium yeast is able to modulate the immune response of rainbow trout, and this effect appears to be both dose- and time-dependent. 相似文献
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Jaroslava Pátková Daniela Šmogrovičová Zoltán Dömény Petra Bafrncová 《Biotechnology letters》2000,22(14):1173-1177
Using calcium alginate-entrapped yeast, 24% (w/w) wort was successfully fermented within 8 days. This is half the time needed for fermentation by free yeast. The highest ethanol concentration obtained was 10.5% (v/v). When the original wort gravity was increased, the specific rate of ethanol production remained constant 0.16 g gh–1 and the viability did not fall bellow 95% of living cells. Protection of cell against osmotic stress by gel matrix was also confirmed by trehalose measurement. The maximum intracellular trehalose content in calcium alginate-entrapped yeast was 3 times lower compared to free yeast at 30% (w/w) wort fermentation. 相似文献
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Jinkun Song # Timothy Townsend Helena Solo-Gabriele Yong-Chul Jang 《Soil & Sediment Contamination》2006,15(4):387-399
The toxicity and mobility of chromium in the environment greatly depends upon its speciation. The reduction of hexavalent chromium to trivalent chromium in a soil environment was examined by spiking three soil types (sandy, clayey, and organic soils) with a common wood preservative solution known as chromated copper arsenate (CCA). Chromium in the CCA preservative solution exists in the hexavalent form. The total and hexavalent chromium concentrations (mg/kg) were measured over a period of 11 months. Leachable chromium concentrations (mg/L) were assessed using the synthetic precipitation leaching procedure (SPLP). The degree and rate of hexavalent chromium reduction were similar for the sand and clayey soil, but much greater for the organic soil. Most of the chromium reduction occurred within the first month of the experiment. At the end of the experiment, approximately 50% of the hexavalent chromium was converted to the trivalent form in the sand and clayey soils. Hexavalent chromium concentrations were below detection in the organic soil at the end of the experiment. Nearly all of the chromium observed in the SPLP leachates was in the form of hexavalent chromium. Chromium leaching was thus greatest in the sand and clay soils where the hexavalent chromium persisted. The results indicate that hexavalent chromium in soils can persist for considerable time periods, in particular in soils with low organic matter content.
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Summary Ethanol concentration and fermentation productivity using Saccharomyces cerevisiae were substantially increased in shake flask cultures with a normal inoculum by combining 3 methods: (a) by making nutrient additions to the standard medium for ethanol production, (b) by immobilizing the cells in alginate beads and (c) by using a glucose step-feeding batch process. Ethanol concentration by free yeast was improved from 5.9% (w/w) to 9.6% (w/w) when a further 0.8% yeast extract and 1% animal peptone were added to the standard 30% (w/v) glucose nutrient medium. This was further increased to 12.8% (w/w) by using alginate immobilized yeast. The ethanol concentration was increased again, to 15.0% (w/w) by using the glucose step-feeding batch process. 相似文献