Effect of Glucose and Fructose in the Protein-repletion Diet Fed after Protein-depletion on Some Blood Constituents of Rats

Percentages of carbohydrates absorbed for 1 day-feeding of protein-repletion diet containing either glucose (glucose-group) or fructose (fructose group) after protein-depletion for 14 days were entirely the same. Some changes in blood constituents of the glucose group and the fructose group were studied. There were no detectable fluctuations in glucose concentration in blood of both groups for varying periods of time of feeding the protein-repletion diet. Whereas, pronounced elevation in fructose concentration in blood was observed for the fructose group. Its values increased for 9hr after feeding the protein-repletion diet containing fructose and then decreased gradually. However, fructose concentration in blood of the glucose group was low. The total carbohydrate concentration (glucose and fructose) in blood of the fructose group increased continuously for 6 hr after feeding the protein-repletion diet and then stayed constant. The total carbohydrate concentration of the fructose group was significantly higher than that of the glucose group except 72 hr-feeding. When the protein-repletion diet was given for 3 days, both liver weight and liver lipid content of the glucose group were significantly lower than those of the fructose group. Allantoin concentration in blood of the fructose group was significantly higher than that of the glucose group. Similarly it was also observed that uric acid level in the serum of the fructose group tended to be higher than that of the glucose group.     

葡萄糖的添加对昆虫细胞Sf21悬浮生长的影响

添加葡萄糖对昆虫细胞Sf21(Spodoptera frugiperda)悬浮生长的影响,发现补加糖量在lg／L时·能明显提高细胞生长的速度和最高密度,细胞最高密度由2．5×10⁴／ml增加到4.9×10⁶／ml; 朴加糖量在2g／L时,则有显著的抑制作用,即使增加接种密度．细胞生长的最高密度也只有2．1×10⁶／ml。当采取流加葡萄糖方法来培养细胞时,则其生长的最大密度可提高到5．2×10⁶／ml。     

Glutamate Dehydrogenase Activity in Lemna perpusilla 6746: The Effects of Sucrose,Glucose and Fructose Addition to Growth Media

Lemna perpusilla Torr, strain 6746 clones were maintained under conditions of continuous illumination with various concentrations of sucrose, glucose or fructose added to the growth, medium. After two weeks of growth, plants were harvested and either assayed for total glutamate dehydrogenase activity or fractionated into one chloroplast-rich and one mitochondria-rich preparation and then assayed for glutamate dehydrogenase activity. In all assays for glutamate dehydrogenase it was necessary to add bovine serum albumin to the extraction medium in order to obtain sufficient enzyme activity for accurate and reproducible results. The presence of sucrose in the growth medium reduced glutamate dehydrogenase activity in all studies. When samples containing intact organelles were assayed, sucrose inhibition of activity appeared to occur primarily in the chloroplast fraction. Glucose, on the other hand, increased glutamate dehydrogenase activity in the chloroplast-rich fractions. Upon freeze-thawing differences between the various treatments were less obvious. The results from these studies indicate possible differences in sugar uptake and/or utilization in Lemna perpusilla.     

Influence of Boar and Semen Parameters on Motility and Acrosome Integrity in Liquid Boar Semen Stored for Five Days

Ninety ejaculates from a total of 76 AI boars were extended in Beltsville Thawing Solution (BTS). Boar identity, breed, weight of the ejaculate and sperm concentration were registered. Motility and acrosome integrity were assessed after storage at 16–18°C for 6, 30, 54, 78, and 102 h. Storage time had a significant influence on both motility (p < 0.01) and acrosome integrity (p < 0.001). The Least Square Means for percentage of motility showed a small decline from 79.8% after 6 h of storage to 78.4% at 102 h. Motility at 78 and 102 h was significantly different from motility at 6 h (p < 0.05). The percentage of sperm cells with normal acrosomes declined throughout the experiment. The Least Square Means for 6, 30, 54, 78, and 102 h of storage were 93.9%, 90.6%, 88.0%, 84.8%, and 78.2%, respectively. The decrease in acrosome integrity from one storage time to the next was highly significant throughout the trial (p < 0.001). There was a significant influence of boar (p < 0.001) and sperm concentration (p < 0.01) on motility, while acrosome integrity was affected only by boar (p < 0.001). Breed of the boars and weight of the ejaculate did not influence the dependent variables.     

Relationship Between ATP Content and Post Thaw Motility in Bull Semen

The ATP content in frozen and thawed semen from 17 bulls was determined by a bioluminescence method. The post thaw motility was assessed by phase contrast microscopy by subjective estimation of the percentage of sperm cells with forward motility. The concentration of spermatozoa was counted in a Bürker chamber. The correlation between ATP content and the number of sperm cells with forward motility was high.     

长双歧杆菌NCC2705葡萄糖与果糖代谢的比较蛋白质组学

为揭示长双歧杆菌NCC2705 (Bifidobacterium longum NCC2705)果糖代谢途径, 建立其果糖发酵模型。以本实验室前期构建的长双歧杆菌NCC2705菌株蛋白质参考图谱为基础, 进行了果糖和葡萄糖生长的菌体比较蛋白质组学研究, 利用MALDI-TOF和ESI-MS/MS鉴定差异蛋白, 进一步通过半定量RT-PCR验证二者显著差异表达蛋白。果糖生长的菌体蛋白中鉴定到了所有葡萄糖降解途径中的酶和蛋白质, 另外鉴定到3倍以上差异蛋白点9个, 其对应的5个蛋白在果糖发酵中上调。半定量RT-PCR验证显著差异蛋白, 显示在果糖发酵中具有高水平表达是ABC 转运系统的果糖特异性-结合蛋白BL0033和ATP结合蛋白BL0034。果糖的发酵时间和浓度梯度试验显示诱导时间越长、浓度越高, BL0033的表达量越高。第一, 比较蛋白谱证明果糖和葡萄糖以相同途径降解。第二, BL0033的表达是受果糖诱导的, 果糖的吸收可能是通过一个特殊的转运系统, 即ABC转运系统将果糖从胞外转运到胞内, 其中BL0033和BL0034共同作为系统元件扮演了重要角色。     

Effect of Fructose Supplementation on Sorbitol Accumulation and myolnositol Metabolism in Cultured Neuroblastoma Cells Exposed to Increased Glucose Concentrations

Aldose reductase activity is increased in neuroblastoma cells grown in media containing 30 mM fructose and/or 30 mM glucose. Neuroblastoma cells cultured in media supplemented with increased concentrations of glucose and fructose amass greater amounts of sorbitol than do cells exposed to media containing only high glucose concentrations. The increase in sorbitol content is dependent on the fructose and glucose concentration in the media. The increase in sorbitol content caused by exposing neuroblastoma cells to media containing 30 mM glucose/30 mM fructose is due to a protein synthesis sensitive mechanism and not to an alteration in the redox state. The addition of sorbinil to media containing 30 mM glucose blocks the increase in sorbitol content. In contrast, sorbinil treatment of media containing 30 mM glucose/30 mM fructose does not totally block the increase in sorbitol levels. myo-Inositol accumulation and incorporation into inositol phospholipids and intracellular myo-inositol content are decreased in cells chronically exposed to media containing 30 mM glucose or 30 mM glucose/30 mM fructose compared to cells cultured in unsupplemented media or media containing 30 mM fructose. However, maximal depletion of myo-inositol accumulation and intracellular content occurs earlier in cells exposed to media containing 30 mM glucose/30 mM fructose than in cells exposed to media supplemented with 30 mM glucose. Sorbinil treatment of media containing 30 mM glucose/30 mM fructose maintains cellular myo-inositol accumulation and incorporation into phospholipids at near normal levels. myo-Inositol content in neuroblastoma cells chronically exposed to media containing 30 mM glucose or 30 mM glucose/30 mM fructose recovers within 72 h when the cells are transferred to unsupplemented media or media containing 30 mM fructose. In contrast, the sorbitol content of cells previously exposed to media containing 30 mM glucose or 30 mM glucose/30 mM fructose then transferred into media containing 30 mM fructose remains elevated compared to the sorbitol content of cells transferred into unsupplemented media. These data suggest that fructose may be activating or increasing sorbinil-resistant aldose reductase activity as well as partially blocking sorbitol dehydrogenase activity. The presence of increased concentrations of fructose in combination with increased glucose levels may enhance alterations in cell metabolism and properties due to increased sorbitol levels.     

Determination of Fructose in the Presence of a Large Excess of Glucose

A modification of the cysteine-sulfuric acid method of Dische and Devi¹¹⁾ is described. The modified procedure is based on the observation that fructose and glucose give different time course of color development. By this modified procedure, fructose in the presence of 100-fold excess of glucose can be determined with an error of about 10%.

Modifications of the anthrone-sulfuric acid method and the phenol-sulfuric acid method are described. By employing the principle of two-point determination of Mokrasch and by modifying the conditions for color development, fructose in the presence of 100-fold excess of glucose can be determined with an error of about 15% by the modified anthrone-sulfuric acid method. The modified phenol-sulfuric acid method also gave the same order of sensitivity and specificity to fructose as the modified anthrone-sulfuric acid method.     

Glucose and Fructose Metabolism in a Phosphoglucoisomeraseless Mutant of Saccharomyces cerevisiae

A mutant of Saccharomyces cerevisiae deficient in phosphoglucoisomerase (EC 5.3.1.9) is described. It does not grow on glucose or sucrose but does grow on galactose or maltose. Addition of glucose to cultures growing on fructose, mannose, or acetate arrests further growth without altering viability; removal of glucose permits resumption of growth. Glucose causes accumulation of nearly 30 mumoles of glucose-6-phosphate per g (wet weight) of cells and suppresses synthesis of ribonucleic acid. Inhibition of growth by glucose does not appear to be due to a loss of adenosine triphosphate or inorganic orthophosphate. The mutant, however, utilizes glucose-6-phosphate produced intracellularly. Release of carbon dioxide from specifically labeled glucose suggests a C-l preferential cleavage. The kinetics of glucose-6-phosphate accumulation during glucose utilization in the mutant is not consistent with the notion that the utilization of glucose is controlled by glucose-6-phosphate.     

Determination of Fructose in the Presence of a Large Excess of Glucose

Some factors affecting the skatole-hydrochloric acid reaction for fructose were studied. Especially, the stability of the chromogen to light, the effect of the amount of chloroform for complete extraction of the chromogen from the aqueous phase, and the time course of color development at various temperatures were studied in some detail. The time course of color development in the β-indolylacetic acid-hydrochloric acid reaction for fructose was also investigated. Based on the results obtained from these observations, some modifications to both the skatole-hydrochloric acid and β-indolylacetic acid-hydrochloric acid reactions were proposed.

A modification of the resorcinol-thiourea-hydrochloric acid method of Roe et al.⁷⁾ for the determination of fructose is described. The modification is based on the observation that by lowering the incubation temperature to 70°C, a greater color intensity ratio (fructose color/glucose color) is obtained, thus increasing the specificity of the method for fructose. By applying the principle of the two-point determination of Mokrasch¹²⁾ to the modified procedure, fructose in the presence of 100-fold excess of glucose can be determined with an error of about 10%.

A modified procedure of the cysteine-carbazole reaction for the determination of fructose is described. By incubating the components of the color reaction at 40°C for 1 hr, fructose is determined with good sensitivity (the millimolar absorbance value of 29.3) and specificity (the color intensity ratio of fructose to glucose is about 240). When the principle of the two-point determination is applied to this modified procedure (1 hr and 3 hr at 40°C), fructose as small an amount as 0.4 μg in the presence of 250-fold excess of glucose can be determined with an error of about 10 %.     

Effects of Gonadotropins on Motility of Human Ovary

THE occurrence of smooth muscle cells in the ovaries of many mammalian species suggests their possible function in the rupture of the ripe follicle by their contractions¹. In the rabbit, pig and sheep ovarian follicles, true smooth muscle cells are present in either or both the theca interna and externa. In women, follicles are surrounded by a network of reticular fibres and cells which resemble smooth muscle cells without fibrils². In a recent report, the ovaries of the cat have not only demonstrated spontaneous contractions in vitro but have also responded to adrenergic stimulation³. On the basis of these findings and in view of the fact that the stromal region of the ovaries of many species, including man, has adrenergic innervation, it has been proposed that contractions of the fibromuscular tissue may play a role in rupture of the follicle and extrusion of the ova³. In this report we describe changes in human intraovarian pressure which seem to result from contraction of the surrounding fibromuscular tissue. In some women marked changes in intraovarian pressure were observed after administration of human menopausal gonadotrophin and chorionic gonadotrophin. The study was carried out in six women of reproductive age who had to undergo abdominal surgery for correction of tubal occlusion (four patients) or tubal ligation. The two patients undergoing tubal ligation were on contraceptive pills for 3–5 years before the operation.     

Na+、葡萄糖、果糖对凹目白鲑精子活力的影响

研究了凹目白鲑（Coregonus autumnalis）精子在302．6～488．9kPa时的NaCl溶液、D-葡萄糖溶液及D-果糖溶液中的活动情况。结果显示,在NaCl溶液中凹目白鲑精子在395．7kPa具最佳活力,其快速运动时间（fast movement time,FT）与寿命时间（1ife time,LT）的最大值分别达43．57s和90．31s;与相同渗透压下NaCl溶液相比,凹目白鲑精子在葡萄糖和果糖溶液中的FT与LT均有不同程度的增加;在葡萄糖溶液中FT与LT的最大值分别为57．67s和97．29s,在果糖溶液中则为70．44s和105．29s。说明凹目白鲑精子活力不但与溶液渗透压有关,而且与溶液溶质有关。     

Characterization of the Biosynthetic Pathway of Cellulose from Glucose and Fructose in Acetobacter xylinum

For characterization of the biosynthetic pathway of cellulose in a cellulose-producing Acetobacter xylinum strain BPR2001, the activities of several enzymes were measured. The activity of phosphoglucose isomerase catalyzing the conversion of fructose-6- phosphate into glucose-6-phosphate was greatly increased by fructose in the medium. The UDP-glucose pyrophosphorylase activity catalyzing the synthesis of UDP-glucose was very high in strain BPR2001, consistent with the idea that this is the key enzyme in cellulose biosynthesis. Strain BPR2001 was found to have a fructose-specific phosphoenolpyruvate-dependent phosphotransferase system (PTS).     

ATP Content and Sperm Motility of Extended Bovine Semen under Different Storage Conditions

The effects of incubation temperature (+20°C vs +35°C) and media type on the ATP content and motility of spermatozoa were determined in fresh bovine semen in order to develop a method for assaying post-thaw quality. Semen was obtained from 3 bulls at 2 occasions. The spermatozoa were washed using a Ficoll-containing medium before being resuspended in each of 4 different media (I. 0.9 % NaCl; II. Trisbuffer solution; III. seminal plasma; IV. seminal plasma + Tris-buffer solution) and incubated for 6 h. The least-squares means for ATP content were higher (p ≤ 0.05) at +20°C than +35°C for all media except no. I. By contrast, the least-squares means for sperm motility were higher (p ≤ 0.05) at +35°C than at +20°C in media II and III. A decrease over time in ATP content and motility at both temperatures was also observed. The single most important factor responsible for changes in ATP content and sperm motility was the temperature and the medium, respectively.     

The Small Intestine Converts Dietary Fructose into Glucose and Organic Acids

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