Influence of alternansucrase-derived oligosaccharides and other carbohydrates on alpha-galactosidase and alpha-glucosidase activity in Bifidobacterium adolescentis.

AIMS: To determine the influence of alternansucrase-derived oligosaccharides (AOS) and other carbohydrates on alpha-galactosidase and alpha-glucosidase activity in Bifidobacterium adolescentis. METHODS AND RESULTS: Activities for alpha-galactosidase and alpha-glucosidase were determined from cell extracts of B. adolescentis grown on 18 test carbohydrates including AOS. alpha-galactosidase activity was enhanced on a variety of alpha-linked or beta-linked carbohydrates regardless of a galactoside or glucoside. alpha-glucosidase, however, was enhanced only on alpha-linked carbohydrates. AOS significantly enhanced enzyme activity compared with most of the carbohydrates tested. Most of the AOS showed significant increases in activity for both enzymes over that displayed by their corresponding acceptor carbohydrates. CONCLUSIONS: alpha-galactosidase may serve as a biomarker for microbial metabolic activity within the large intestine for potential prebiotics composed of alpha-linked or beta-linked oligosaccharides whereas alpha-glucosidase activity may be restricted to assessing the influence of only alpha-linked carbohydrates. The AOS synthesis process provided a value-added component to carbohydrates by increasing metabolic activity (via alpha-galactosidase and alpha-glucosidase) over certain acceptor carbohydrates. SIGNIFICANCE AND IMPACT OF THE STUDY: Fundamental knowledge of enzyme activity in Bifidobacterium may aid in the design of more effective prebiotics and may also help identify enzyme indicators of metabolic activity when assessing influence within the intestine.     

哺乳动物肠道微生物与碳水化合物的互作及其影响

肠道微生物具有调节宿主营养、免疫以及能量代谢等生理功能。饮食是影响哺乳动物的肠道微生物的一个重要因素。碳水化合物是哺乳动物食物能量的主要来源,因此研究肠道微生物与碳水化合物的代谢之间的关系及其影响具有重要意义。基于近年相关研究,本文从碳水化合物对肠道微生物组成的影响、肠道微生物对碳水化合物的代谢机制以及碳水化合物发酵产物短链脂肪酸对宿主的影响3个方面进行了综述。研究表明,肠道微生物可用于发酵的碳水化合物类型主要是抗性淀粉和非淀粉多糖;不同类型的碳水化合物会导致肠道菌群发生适应性变化;复杂多糖发酵产生的短链脂肪酸在调节宿主能量平衡和免疫应答方面发挥了重要作用。总结近年来相关研究,可加深对肠道菌群对宿主碳水化合物代谢贡献的理解,为哺乳动物机体健康状况的营养调控策略提供参考。     

Histochemistry of carbohydrates in the epithelium lining the bulbourethral gland of the rat

The histochemistry of carbohydrates has been studied in the epithelium lining the bulbourethral gland of the rat by means of light- and electron-microscopic methods. The results obtained show that the cytoplasms of the epithelial cells contain neutral and acidic carbohydrates. The neutral carbohydrates exhibited positive reactions with periodic acid-Schiff and periodic acid-thiosemicarbazide-silver proteinate, whereas the acidic carbohydrates reacted positively with alcian blue (AB; pH 1.0 and 2.5) and dialyzed iron. Most neutral carbohydrates were found to be glycoproteins localized within the secretory granules. The acidic carbohydrates consist of at least two types, AB (pH 1.0)-reactive sulfated and AB (pH 2.5)-reactive nonsulfated carbohydrates; most nonsulfated carbohydrates were determined to be sialic acid. The acidic carbohydrates were also localized within the secretory granules.     

糖类结构的光谱分析的特点

光谱分析方法是糖生物学化学方面研究及开发的关键技术手段。由于糖类物质种类繁多、结构多样、构效关系极为复杂,如何合理高效使用波谱分析这一便捷方法,对于糖类物质的准确分析尤为重要,文章重点分析了现代波谱技术,如红外光谱、核磁共振、质谱等在糖生物学研究和化学化工领域的应用特点,特别指出糖分析中需要注意的一些特殊性,以促进谱学分析技术在糖生物医学、化学等领域的有效应用。     

Type 2 chain glycosylation in thyroid carcinomas

Alterations of cell-surface carbohydrates are important for the metastatic behaviour of human carcinomas. Follicular and papillary thyroid carcinomas clinically show a very different metastatic pattern and represent a good model for studies of the metastatic process. We examined the expression of various Le^x-related carbohydrates in 30 primary papillary, 20 primary follicular and 15 primary anaplastic thyroid carcinomas by means of immunohistochemistry. Six metastases from papillary and five from follicular carcinomas were also examined. Morphologically normal thyroid epithelium did not express any of the type 2 carbohydrates. Papillary carcinomas were immunoreactive for several type 2 carbohydrates, including sialyl-Lewis X, in contrast to follicular and anaplastic carcinomas. The metastases showed no significant differences in expression of carbohydrates compared with the primary tumours. We hypothesize that the up-regulation of sialyl-Lewis X and some other related carbohydrates in papillary carcinomas is of importance for the clinical behaviour of these tumours.     

Chinese hamster ovary cell mutants with multiple glycosylation defects for production of glycoproteins with minimal carbohydrate heterogeneity.

The production of glycoproteins with carbohydrates of defined structure and minimal heterogeneity is important for functional studies of mammalian carbohydrates. To facilitate such studies, several Chinese hamster ovary mutants that carry between two and four glycosylation mutations were developed. All of the lines grew readily in culture despite the drastic simplification of their surface carbohydrates. Therefore, both endogenous glycoproteins and those introduced by transfection can be obtained with specifically tailored carbohydrates. The lectin resistance properties of the mutants showed that each line expresses a novel array of cell surface carbohydrates useful for identifying specific roles for carbohydrates in cellular interactions. In addition, they showed that the epistatic relationships among different glycosylation mutations are not entirely predictable, providing insight into the complexity of the carbohydrate structures at the Chinese hamster ovary cell surface.     

Integrity of glycoprotein complex sugars is required for homing but not for several other membrane-mediated functions

In order to correlate the biochemistry of cell surface carbohydrates with cell function, we have treated cells with swainsonine and followed the biochemical and functional modifications induced by this compound. After treatment with swainsonine, surface glycoproteins had a lower apparent molecular weight and a higher isoelectric point. This is compatible with the replacement of complex carbohydrates by hybrid or high-mannose carbohydrates. Several functional tests were unaffected. However, swainsonine-treated cells displayed an altered pattern of in vivo homing, suggesting that carbohydrates play a role in this process.     

植物非结构性贮藏碳水化合物的生理生态学研究进展

非结构性碳水化合物是参与植物生命过程的重要物质。蔗糖不仅是植物体内碳水化合物运输的主要形式,而且可以在基因表达水平上对细胞内的代谢进行调节。果聚糖是植物营养组织碳水化合物的主要暂贮形式;淀粉是植物主要的长期贮存物质之一。植物体内非结构性碳水化合物的代谢在很大程度上影响着植株的生长发育和对环境因子的响应。综述了植物非结构性贮藏碳水化合物的生理生态学研究进展,着重介绍了蔗糖,果聚糖和淀粉代谢的生理过程及对环境因子（温度和水分）和人为因素的响应机制。     

D2O effects on association behavior and binding properties of phospho- and dephospho-cytoplasmic malic dehydrogenase

Changes in the concentration of three major carbohydrates, e.g., glycogen, trehalose, and cellulose, were determined during differentiation of Dictyostelium discoideum in a stage study. These three carbohydrates consituted 50–63% of the total carbohydrates. Total carbohydrate content per cell aliquot did not change between the aggregation and sorocarp stages of differentiation. The isolation, purification, and characterization of cellulose is described. Cellulose consisted of an alkali-insoluble (alpha) and an alkali-soluble (beta) fraction. Total cellulose accumulated from very low amounts in late pseudoplasmodium cells to about 35% of carbohydrates in mature sorocarps at a rate of 0.07 μmole glucose equiv/min/ml packed cell volume. Purified alkali-insoluble cellulose constituted about 19% of total carbohydrates in mature sorocarps and accumulated at a rate of 0.035 μmole glucose equiv/min/ml packed cell volume. Trehalose constituted 10–11% of the carbohydrates in sorocarps and accumulated at a rate of 0.035 μmole glucose equiv/min/ml packed cell volume. Glycogen, comparing several methods of determination, was rapidly degraded between the culmination and sorocarp stages of differentiation at an average rate of 0.05 μmole glucose equiv/min/ml packed cell volume. The major portion of glycogen was soluble in TCA and constituted 35% of total carbohydrates in aggregated cells and about 11% in mature sorocarps. A minor fraction of glycogen, about 15% of total carbohydrates in aggregated cells, was solubilized by KOH from a TCA precipitate. A mild acidic treatment of solubilized cell constituents increased the glycogen content by 55%, as judged by an enzymatic assay.     

Carbohydrate sources and sinks in woody plants

Each perennial woody plant is a highly integrated system of competing carbohydrate sinks (utilization sites). Internal competition for carbohydrates is shown by changes in rates of carbohydrate movement from sources to sinks and reversals in direction of carbohydrate transport as the relative sink strengths of various organs change. Most carbohydrates are produced in foliage leaves but some are synthesized in cotyledons, hypocotyls, buds, twigs, stems, flowers, fruits, and strobili. Although the bulk of the carbohydrate pool moves to sinks through the phloem, some carbohydrates are obtained by sinks from the xylem sap. Sugars are actively accumulated in the phloem and move passively to sinks along a concentration gradient. The dry weight of a mature woody plant represents only a small proportion of the photosynthate it produced. This discrepancy results not only from consumption of plant tissues by herbivores and shedding of plant parts, but also from depletion of carbohydrates by respiration, leaching, exudation, secretion, translocation to other plants through root grafts and mycorrhizae and losses to parasites. Large spatial and temporal variations occur in the use of reserve- and currently produced carbohydrates in metabolism and growth of shoots, stems, roots, and reproductive structures. A portion of the carbohydrate pool is diverted for production of chemicals involved in defense against fungi, herbivores, and competing plants. Woody plants accumulate carbohydrates during periods of excess production and deplete carbohydrates when the rate of utilization exceeds the rate of production. Stored carbohydrates play an important role in metabolism, growth, defense, cold hardiness, and postponement or prevention of plant mortality.     

Concanavalin A-perioxidase-diaminobenzidine (Con-A-PO-DAB)-alcian blue (AB): a reliable method for dual staining of complex carbohydrates.

A method has been established for the dual staining of complex carbohydrates in light microscopy. It is a combined concanavalin A-peroxidase-diaminobenzidine (Con-A-PO-DAB)-alcian blue (AB) (pH 2.5) method, and with this method it is possible to color alpha-D-glucosyl and alpha-D-mannosyl residues and acidic groupings of complex carbohydrates in tissues brown and blue respectively. Histochemical experiments using histological sections with reactive complex carbohydrates and casein films containing carbohydrates of known chemical structure have substantiated the validity of the above significance of the dual staining. Thus, the present dual staining method is a reliable one and a new addition to a series of dual staining techniques hitherto employed in the light microscopic histochemistry of complex carbohydrates.     

Osmoregulation in halophytic higher plants: a comparative study of soluble carbohydrates, polyols, betaines and free proline

Abstract. The levels of soluble carbohydrates, polyols, betaines and free proline have been determined in different organs of sixteen plants collected on coastal salt marshes. Among the carbohydrates, sucrose, fructose and glucose accumulated at quite high levels. Sucrose is particularly abundant in the monocots Juncus maritima, Phragmites communis and Scirpus maritimus. Maltose is quite abundant in Atriplex hastata and rhamnose in Plantago maritima roots. High levels of polyols were detected in Aster tripolium, Juncus maritimus, Plantago maritima and Phragmites communis. According to their capacity to accumulate carbohydrates and (or) nitrogenous solutes, halophytic higher plants can be divided into three main groups: (1) species producing high levels of soluble carbohydrates only, (2) species accumulating both carbohydrates and nitrogenous compounds, (3) species producing more nitrogenous solutes than soluble carbohydrates. The possible functions of these various organic solutes, including a role in equalizing the relative water potentials of cytoplasm and vacuole and to lower the internal potential, are discussed.     

Carbohydrates in the functions of natural killer cells.

There is little doubt that carbohydrates are crucial to the functions of NK cells. Exogenous carbohydrates alter the cytolytic capabilities of these cells, treatment of NK cells with glycosidases or inhibitors of glycosylation affect function, NK cells can bind selective sugars, and NK cells can be identified and subdivided into functionally distinct subsets on the basis of cell surface carbohydrates. Yet, despite the large number of observations which have been made concerning carbohydrates and NK cells, there is little consensus regarding these studies and few investigations which satisfactorily demonstrate specific mechanisms for the observed effect of the carbohydrates. Almost certainly, the number of diverse observations implies roles for carbohydrates in multiple areas of NK function, probably including target recognition, tissue distribution and post-binding events in the lytic cascade. Hopefully, these observations made to date will be viewed as exciting preliminary studies which will entice more sophisticated investigations designed to elucidate the precise roles of carbohydrates in the functions of NK cells.     

Carbohydrate utilization by normal and γ-sterilized Dacus oleae

Non-sterilized adult olive fruit flies were able to survive and reproduce on mannose, glucose, fructose, sucrose, melibiose, trehalose, maltose, melezitose, and sorbitol, out of a series of 23 carbohydrates γ-sterilized flies were able to utilize the same carbohydrates with the exception of melezitose, indicating that sterilization with a 10 Krad dose did not affect their ability to utilize various carbohydrates. Since these carbohydrates are common constituents of the fly's natural food sources, the released sterile flies should be able to survive satisfactorily in the field. The possible presence of three carbohydrases is discussed.     

The carbohydrates of submerged mycelium of xylotrophic basidiomycetes

It was demonstrated that the total content of carbohydrates in the submerged mycelium of xylotrophic basidiomycetes falls into the range of 34.66-57.57%. Free carbohydrates of the cell cytosol amounted to 14.52-28.64%; structural carbohydrates, to 20.14-32.70%. Qualitative composition of carbohydrates was studied, which allowed for attributing structural polysaccharides to hetero- and homoglycans with beta- and alpha-glycoside bonds.     

Carbohydrates for fermentation

Biomass accumulated by the photosynthetic fixation of carbon dioxide is the only renewable carbon source, and hence, the only renewable raw material for the chemical industry. Carbohydrates are the main constituents of biomass and occur as cell wall and storage carbohydrates, transportation carbohydrates and glycoconjugates. Cellulose, hemicelluloses and starch in particular as well as pectin, inulin and saccharose to a smaller extent are the most abundant carbohydrates. Glucose is the most important monosaccharide and monomer of polysaccharides in natural carbohydrates. Thus, it is the most abundant organic compound on earth. Production of pulp from wood cellulose, applications of starch for paper making as well as uses of glucose and saccharose for fermentation are the most important chemical and technical uses of carbohydrates. Carbohydrates used as fermentation feedstock are essential for the chemical industry. Their importance is steadily growing due to the increasing implementation of biotechnological processes.     

The histochemistry of complex carbohydrates in the scrotum of the boar

Summary In the scrotal skin of the boar, the histochemistry of complex carbohydrates has been studied by means of a series of selected methods of light microscopy. The epidermis of the scrotal skin was found to contain neutral and acidic complex carbohydrates with different saccharide residues. The secretory epithelial cells and secretory substances of the saccular apocrine sweat glands contained sulfated, other acidic and neutral complex carbohydrates, whereas the secretory epithelial cells and secretory substances of the tubular apocrine sweat glands involved largely neutral complex carbohydrates. The two types of complex carbohydrates from the both glands were shown to contain commonly substantial amounts of various saccharide residues but were devoid of notable amounts of sialic acid residues. In addition, complex carbohydrates in the smooth muscle cells were reacted for relatively small amounts of saccharide residues. From the present results, the histophysiological significanses of complex carbohydrates in the particular histologic structures of the scrotum have been discussed with special reference to the functions of the skin in the boar.A major part of this work has been presented at the 6th International Histochemistry and Cytochemistry Congress, Brighton, United Kingdom, in 1980     

The histochemistry of complex carbohydrates in the testes of patients of idiopathic male infertility

Summary In testis tissues from patients with idiopathic male infertility, complex carbohydrates have been studied by means of light microscopic histochemical methods, comparisons being made with the normal testes. In the infertile testes, histochemical reactions for acidic and neutral complex carbohydrates were in general weaker in intensity than in the normal testes. In the seminiferous tubules and interstitium of the infertile testes, a histochemical finding of primary importance was obtained with the demonstration of galactose deficiency in the complex carbohydrates involved. These glycoproteins contained only small numbers of sulfhydryl and disulfide groups. The possible histophysiological significance of these complex carbohydrates is discussed, with special reference to their histochemical properties determined in the present study.     

Steroidal regulation of hydrolyzing activity of the dietary carbohydrates in the silkworm, Bombyx mori

Blood sugar is an essential energy source for growth and development and is maintained at a constant level through precise regulation of formation and utilization. Sugars are produced from dietary carbohydrates by enzymatic hydrolysis in the digestive tract, which are under the homeostatic control of paracrine and prandial mechanisms in mammals. Here, we show that dietary carbohydrates hydrolyzing activity of the digestive tract is developmentally regulated by the steroid hormone ecdysone in the silkworm, Bombyx mori. The dietary carbohydrates hydrolyzing activity remained high throughout the last larval period and then decreased to negligible levels until the pupal period. However, dietary carbohydrates digestive activities were constitutively high when the steroidogenic organ, prothoracic glands were ablated. The prothoracic glands produced and released a large amount of ecdysone at the end of the larval period, suggesting that ecdysone is responsible for the decrease in dietary carbohydrates hydrolyzing activity. In fact, ecdysone decreased the activity to negligible levels in silkworms lacking the prothoracic glands. The present results indicate that the dietary carbohydrates hydrolyzing activity is regulated by ecdysone and that an increase in ecdysone titer decreases that activity at the end of the larval period, suggesting that ecdysone is essential for metabolic coordination during development.     

Oligosaccharide microarrays fabricated on aminooxyacetyl functionalized glass surface for characterization of carbohydrate-protein interaction

Carbohydrate-protein interactions play important biological roles in biological processes. But there is a lack of high-throughput methods to elucidate recognition events between carbohydrates and proteins. This paper reported a convenient and efficient method for preparing oligosaccharide microarrays, wherein the underivatized oligosaccharide probes were efficiently immobilized on aminooxyacetyl functionalized glass surface by formation of oxime bonding with the carbonyl group at the reducing end of the suitable carbohydrates via irreversible condensation. Prototypes of carbohydrate microarrays containing 10 oligosaccharides were fabricated on aminooxyacetyl functionalized glass by robotic arrayer. Utilization of the prepared carbohydrate microarrays for the characterization of carbohydrate-protein interaction reveals that carbohydrates with different structural features selectively bound to the corresponding lectins with relative binding affinities that correlated with those obtained from solution-based assays. The limit of detection (LOD) for lectin ConA on the fabricated carbohydrate microarrays was determined to be approximately 0.008 microg/mL. Inhibition experiment with soluble carbohydrates also demonstrated that the binding affinities of lectins to different carbohydrates could be analyzed quantitatively by determining IC(50) values of the soluble carbohydrates with the carbohydrate microarrays. This work provides a simple procedure to prepare carbohydrate microarray for high-throughput parallel characterization of carbohydrate-protein interaction.