Different effects of galactose and mannose on cell proliferation and intracellular soluble sugar levels in <Emphasis Type="Italic">Vigna angularis</Emphasis> suspension cultures

Plant cells utilize various sugars as carbon sources for growth, respiration and biosynthesis of cellular components. Suspension-cultured cells of azuki bean (Vigna angularis) proliferated actively in liquid growth medium containing 1% (w/v) sucrose, glucose, fructose, arabinose or xylose, but did not proliferate in medium containing galactose or mannose. These two latter sugars thus appeared distinct from other sugars used as growth substrates. Galactose strongly inhibited cell growth even in the presence of sucrose but mannose did not, suggesting a substantial difference in their effects on cell metabolism. Analysis of intracellular soluble-sugar fractions revealed that galactose, but not mannose, caused a conspicuous decrease in the cellular level of sucrose with no apparent effects on the levels of glucose or fructose. Such a galactose-specific decrease in sucrose levels also occurred in cells that had been cultured together with glucose in place of sucrose, suggesting that galactose inhibits the biosynthesis, rather than uptake, of sucrose in the cells. By contrast, mannose seemed to be metabolically inert in the presence of sucrose. From these results, we conclude that sucrose metabolism is important for the heterotrophic growth of cells in plant suspension-cultures.     

Golgi Apparatus Mediated Polysaccharide Secretion by Outer Root Cap Cells of Zea mays. III. Control by Exogenous Sugars

Sugars supplied to germinating seedlings of maize (Zea mays L.) regulate the secretion of polysaccharides by the outer cells of the root cap. The polysaccharide secreted by these cells adheres to the root tip as a droplet and the size of the droplet was used to quantitate polysaccharide secretion. The polysaccharide contains glucose, galacrose, and galacturonic acid residues with smaller quantities of mannose, arabinose, xylose, fucose and rhamnose. These sugars supplied to maize seedlings had marked effects on the rate of polysaccharide secretion by root tips. The effects on secretion were independent of the growth rates of the roots. Glucose, fucose and xylose increased droplet size 1.5–2 fold (as did sucrose, maltose, lacrose, fructose and ribose) whereas galactose, arabinose and galacturonic acid were inhibitory. Mannose increased dropler size 5–7 fold. The marked effect of mannose on polysaccharide secretion was due to an increased rate of secretion combined with a longer phase of extrusion of polysaccharide into the forming droplet. The effect of mannose was partially reversed by inorganic phosphate and other sugars (except for fucose which had no effect or promoted secretion in the presence of mannose). In contrast to sucrose, mannose stimulated secretion in a maize variety having a high sugar endosperm (high endogenous sugar). The results suggest that regulation of secretion by mannose is due to an alteration of normal sugar metabolism; whereas stimulation of secretion by sucrose and other sugars may be due to an increased availability of sugars for metabolism.     

Carbohydrate utilization patterns and substrate preferences in Bacteroides thetaiotaomicron

Specific growth rates of Bacteroides thetaiotaomicron NCTC 10582 with either glucose, arabinose, mannose, galactose or xylose as sole carbon sources were 0.42/h, 0.10/h, 0.38/h, 0.38/h and 0.16/h respectively, suggesting that hexose metabolism was energetically more efficient than pentose fermentation in this bacterium. Batch culture experiments to determine whether carbohydrate utilization was controlled by substrate-induced regulatory mechanisms demonstrated that mannose inhibited uptake of glucose, galactose and arabinose, but had less effect on xylose. Arabinose and xylose were preferentially utilized at high dilution rates (D > 0.26/h) in carbon-limited continuous cultures grown on mixtures of arabinose, xylose, galactose and glucose. When mannose was also present, xylose was co-assimilated at all dilution rates. Under nitrogen-limited conditions, however, mannose repressed uptake of all sugars, showing that its effect on xylose utilization was strongly concentration dependent. Studies with individual D-ZU-14C]-labelled substrates showed that transport systems for glucose, galactose, xylose and mannose were inducible. Measurements to determine incorporation of these sugars into trichloroacetic acid-precipitable material indicated that glucose and mannose were the principal precursor monosaccharides. Xylose was only incorporated into intracellular macromolecules when it served as growth substrate. Phosphoenolpyruvate:phosphotransferase systems were not detected in preliminary experiments to elucidate the mechanisms of sugar uptake, and studies with inhibitors of carbohydrate transport showed no consistent pattern of inhibition with glucose, galactose, xylose and mannose. These results indicate the existence of a variety of different systems involved in sugar transport in B. thetaiotaomicron.     

Succinic acid production by <Emphasis Type="Italic">Actinobacillus succinogenes</Emphasis> from batch fermentation of mixed sugars

Succinic acid production from the monosaccharides xylose, arabinose, glucose, mannose and galactose was studied using the bacterium Actinobacillus succinogenes. In Duran bottle cultures, containing 10 g/L of each of sugar, succinic acid was produced from all sugars except for galactose. The highest succinate yield, 0.56 g/g, was obtained with glucose, whereas the succinate yield was 0.42, 0.38 and 0.44 g/g for xylose, mannose and arabinose, respectively. The specific succinate productivity was 0.7 g/g h for glucose, but below 0.2 g/g h for the other sugars. Batch bioreactor fermentations were carried out using a sugar mixture of the five sugars giving a total concentration of 50 g/L, mimicking the distribution of sugars in spent sulfite liquor (SSL) from Eucalyptus which is rich in xylose. In this mixture, an almost complete conversion of all sugars (except galactose) was achieved resulting in a final succinate concentration of 21.8–26.8 g/L and a total yield of 0.59–0.68 g/g. There was evidence of co-consumption of glucose and xylose, whereas mannose was consumed after glucose. The main by-products were acetate 0.14–0.20 g/g and formate 0.08–0.13 g/g. NADH balance calculations suggested that NADH required for succinate production was not met solely from formate and acetate production, but other means of NADH production was necessary. Results from mixed sugar fermentations were verified using SSL as substrate resulting in a succinate yield of 0.60 g/g. In addition, it was found that CO₂ sparging could replace carbonate supply in the form of MgCO₃ without affecting the succinate yield.     

Chemical Studies on the Cell Walls of Leptospira biflexa Strain Urawa and Treponema pallidum Strain Reiter

The preparation and chemical poperties of the cell walls of Leptospira biflexa Urawa and Treponema pallidum Reiter are described. Both cell walls are composed mainly of polysaccharides and peptidoglycans. The data of chemical analysis indicate that the cell wall of L. biflexa Urawa contains rhamnose, arabinose, xylose, mannose, galactose, glucose and unidentified sugars as neutral sugars, and alanine, glutamic acid, α,ε-diaminopimelic acid, glucosamine and muramic acid as major amino acids and amino sugars. As major chemical constituents of the cell wall of T. pallidum Reiter, rhamnose, arabinose, xylose, mannose, galactose, glucose, alanine, glutamic acid, ornithine, glycine, glucosamine and muramic acid have been detected. The chemical properties of protein and polysaccharide fractions prepared from the cells of T. pallidum Reiter were also partially examined.     

Effect of some disaccharides, hexoses and pentoses on nitrate reductase, glutamine synthetase and glutamate dehydrogenase in excised pea roots

The effects of exogenous sucrose, lactose, d -glucose, d (-)fructose, d -galactose, d -mannose, l -sorbose, l -arabinose and d -xylose on nitrate reductase (NR), glutamine synthetase (GS) and glutamate dehydrogenase (GDH) levels, on anaerobic nitrite production and on respiratory O₂ consumption were studied in excised roots of pea (Pisum sativum L. cv. Raman). Sucrose, glucose and fructose increase NR and GS levels and decrease GDH level (when compared with roots cultures without any sugar) at all concentrations used, but the extent of this effect varies. NR induction is enhanced by all sugars within the concentration range studied. Precultivation of roots with mannose and galactose results in an increase in anaerobic nitrite production in a medium consisting of phosphate buffer and KNO₃. GS reaches its maximum at lower sugar concentrations, this fact being especially clear-cut with galactose. The decrease in GS level observed in roots cultured without sucrose is enhanced by higher sorbose concentrations. The increase in GDH level occurring in roots cultured without sucrose is depressed by low galactose and mannose concentrations but enhanced by high galactose, mannose, xylose and a wide range of sorbose concentrations. Lactose exerts only slight influence on the enzymes. The effects of sugars are in no case consistent with their effect on respiratory O₂ consumption which is most pronounced with NR. The above results show that the effects of sugars on NR, GS and GDH are not mediated by one universal mechanism.     

"GIGANTISM" OF CHLORELLA VULGARIS I. RELATION OF GIGANTISM TO CELL GROWTH AND DIVISION

1. The sugars which induced gigantism of Chlorella cells wereglucose,fructose, galactose, mannose, xylose and arabinose.These sugarswere utilized as respiratory substrates by thealgal cells.
2. The cellular division of Chlorella was stimulatedby glucoseand galactose, but suppressed by fructose, mannose,xylose andarabinose, while all these sugars evoked gigantism.No correlationwas found between cellular division and gigantism,
3. The photosynthetic activity of giant Chlorella varied withthesorts of sugars added. It was decreased by glucose, fructoseand mannose, but was unaffected by other sugars such as galactose,xylose and arabinose.
4. The respiratory activity of giant Chlorellacells as much higherthan that of control cells.
5. The amountsof protein-N and dry weight per unit volume of giantChlorellawere much less than those of control cells.

¹ Present address: Department of Chemistry, College of GeneralEducation, Osaka University, Toyonaka, Osaka.     

Carbohydrates from hydrocarbons. II. Free and bound sugars from yeast cells grown on n-hexadecane.

Candida lipolytica (strain 10) was grown on an n-hexadecane medium with and without yeast extract. The harvested dry cells were weighed at various stages of growth. The free sugars from the cultures were obtained by Soxhlet extraction with 85% ethyl alcohol. Further qualitative and quantitative analyses of free monosaccharides in the concentrated alcoholic extracts were made by paper chromatography. Glucose was the only free monosaccharide that could be identified at various stages of growth. The chromatographic analysis of the acid-hydrolyzed yeast cells indicated the presence of glucose and mannose as dominant bound sugars; galactose and xylose were present in minor quantities. In the harvested dry cells from the yeast extract-containing medium, in general, greater amounts of bound sugars were present.     

Novel endophytic yeast Rhodotorula mucilaginosa strain PTD3 I: production of xylitol and ethanol

An endophytic yeast, Rhodotorula mucilaginosa strain PTD3, that was isolated from stems of hybrid poplar was found to be capable of production of xylitol from xylose, of ethanol from glucose, galactose, and mannose, and of arabitol from arabinose. The utilization of 30 g/L of each of the five sugars during fermentation by PTD3 was studied in liquid batch cultures. Glucose-acclimated PTD3 produced enhanced yields of xylitol (67% of theoretical yield) from xylose and of ethanol (84, 86, and 94% of theoretical yield, respectively) from glucose, galactose, and mannose. Additionally, this yeast was capable of metabolizing high concentrations of mixed sugars (150 g/L), with high yields of xylitol (61% of theoretical yield) and ethanol (83% of theoretical yield). A 1:1 glucose:xylose ratio with 30 g/L of each during double sugar fermentation did not affect PTD3's ability to produce high yields of xylitol (65% of theoretical yield) and ethanol (92% of theoretical yield). Surprisingly, the highest yields of xylitol (76% of theoretical yield) and ethanol (100% of theoretical yield) were observed during fermentation of sugars present in the lignocellulosic hydrolysate obtained after steam pretreatment of a mixture of hybrid poplar and Douglas fir. PTD3 demonstrated an exceptional ability to ferment the hydrolysate, overcome hexose repression of xylose utilization with a short lag period of 10 h, and tolerate sugar degradation products. In direct comparison, PTD3 had higher xylitol yields from the mixed sugar hydrolysate compared with the widely studied and used xylitol producer Candida guilliermondii.     

Carbohydrate utilization by Trichomonas gallinae: effects on growth and metabolic activity under nongrowth conditions

Trichomonas gallinae used 13 of 29 carbohydrates for growth. Quantitative relationships between final populations, acid production, and cellular glycogen contents varied depending on the substrate. The effect of growth on different carbohydrates on the subsequent utilization of carbohydrates by cells under nongrowth conditions was studied by measuring carbohydrate uptake, changes in cellular glycogen content, and gas production. Two major utilization patterns were found. Cells grown on maltose or starch used these substrates well, but cells grown on other sugars did not. All cells used glucose, fructose, galactose, and mannose, but cells grown on maltose or starch did not use them as well as cells grown on other sugars. All cells used ribose slightly but not xylose or arabinose. Turanose, a disaccharide yielding high populations in growth medium, was not used under nongrowth conditions.     

Glycan Residues Balance Analysis - GReBA: A novel model for the N-linked glycosylation of IgG produced by CHO cells

The structure of N-linked glycosylation is a very important quality attribute for therapeutic monoclonal antibodies. Different carbon sources in cell culture media, such as mannose and galactose, have been reported to have different influences on the glycosylation patterns. Accurate prediction and control of the glycosylation profile are important for the process development of mammalian cell cultures. In this study, a mathematical model, that we named Glycan Residues Balance Analysis (GReBA), was developed based on the concept of Elementary Flux Mode (EFM), and used to predict the glycosylation profile for steady state cell cultures. Experiments were carried out in pseudo-perfusion cultivation of antibody producing Chinese Hamster Ovary (CHO) cells with various concentrations and combinations of glucose, mannose and galactose. Cultivation of CHO cells with mannose or the combinations of mannose and galactose resulted in decreased lactate and ammonium production, and more matured glycosylation patterns compared to the cultures with glucose. Furthermore, the growth rate and IgG productivity were similar in all the conditions. When the cells were cultured with galactose alone, lactate was fed as well to be used as complementary carbon source, leading to cell growth rate and IgG productivity comparable to feeding the other sugars. The data of the glycoprofiles were used for training the model, and then to simulate the glycosylation changes with varying the concentrations of mannose and galactose. In this study we showed that the GReBA model had a good predictive capacity of the N-linked glycosylation. The GReBA can be used as a guidance for development of glycoprotein cultivation processes.     

Influence of essential oil of Hyssopus officinalis on the chemical composition of the walls of Aspergillus fumigatus (Fresenius)

The cell walls of the growing hyphae of Aspergillus fumigatus (Fresenius) cultured in the presence or absence of the essential oil of Hyssopus officinalis were isolated and their chemical composition analysed. The presence of the essential oil led to a reduction in levels of neutral sugars, uronic acid and proteins, whereas amino sugars, lipids and phosphorus levels were increased. HPLC analysis of the neutral sugars showed that they consisted mainly of glucose, mannose and galactose, while the amino sugars consisted of glucosamine and galactosamine. The presence of the essential oil in the culture medium induced marked changes in the content of galactose and galactosamine. Cell walls were fractionated by treatment with alkali and acid. The essential oil induced similar alterations in the various fractions with a more marked effect on the major constituents. The alterations were related to changes in the structure of the cells. This revised version was published online in August 2006 with corrections to the Cover Date.     

不同碳源对大肠杆菌lpdA突变菌累积丙酮酸的影响

为了利用大肠杆菌构建模式"细胞工厂",必须了解在构建过程中各种因素的影响。本研究选用敲除了lpdA基因的大肠杆菌作为模型细胞,考察了该突变菌在合成培养基中利用葡萄糖、果糖、木糖和甘露糖累积丙酮酸的能力。结果显示,在初始糖浓度为10g/L的情况下,lpdA突变菌可以很好地利用葡萄糖、果糖、木糖和甘露糖转化丙酮酸,其得率分别达到了0.884g/g、0.802g/g、0.817g/g和0.808g/g,且在以葡萄糖、果糖和木糖发酵时,丙酮酸的积累过程与细胞生长偶联。甘露糖发酵的情况则不同:菌浓度很快达到平台期,随后丙酮酸积累和甘露糖消耗都表现为线性变化。当在考察了不同的接种量对lpdA突变菌发酵葡萄糖的影响时发现,大接种量能加快葡萄糖消耗速率、丙酮酸的积累速率和细胞生长速率,但丙酮酸得率却明显下降。这些结果对构建以大肠杆菌为母体的模式"细胞工厂"有参考价值。     

Utilization of some monosaccharides by two species of Colletotrichum

Summary Utilization of 8 monosaccharides, viz., glucose, fructose, galactose, mannose, sorbose, arabinose, xylose and rhamnose, by some plant pathogenic isolates ofColletotrichum gloeosphorioides andC. dematium has been studied with the help of paper chromatography. Among hexoses, the rate of utilization of glucose, fructose and mannose was fast, whereas, that of galactose was comparatively slow. The rate of assimilation of sorbose was very slow at early stages of incubation, although at later stages this rate showed marked enhancement. The pentoses were utilized readily. The dry weight of mycelial mats showed an increase up to the end of final incubation period (15 days), on sugars which were slowly assimilated. In cases where the sugars were consumed up rapidly, the dry weight at later stages of incubation either became nearly stationary or recorded slight fall.     

Bioconversion of lignocellulose-derived sugars to ethanol by engineered Saccharomyces cerevisiae

Lignocellulosic biomass from agricultural and agro-industrial residues represents one of the most important renewable resources that can be utilized for the biological production of ethanol. The yeast Saccharomyces cerevisiae is widely used for the commercial production of bioethanol from sucrose or starch-derived glucose. While glucose and other hexose sugars like galactose and mannose can be fermented to ethanol by S. cerevisiae, the major pentose sugars D-xylose and L-arabinose remain unutilized. Nevertheless, D-xylulose, the keto isomer of xylose, can be fermented slowly by the yeast and thus, the incorporation of functional routes for the conversion of xylose and arabinose to xylulose or xylulose-5-phosphate in Saccharomyces cerevisiae can help to improve the ethanol productivity and make the fermentation process more cost-effective. Other crucial bottlenecks in pentose fermentation include low activity of the pentose phosphate pathway enzymes and competitive inhibition of xylose and arabinose transport into the cell cytoplasm by glucose and other hexose sugars. Along with a brief introduction of the pretreatment of lignocellulose and detoxification of the hydrolysate, this review provides an updated overview of (a) the key steps involved in the uptake and metabolism of the hexose sugars: glucose, galactose, and mannose, together with the pentose sugars: xylose and arabinose, (b) various factors that play a major role in the efficient fermentation of pentose sugars along with hexose sugars, and (c) the approaches used to overcome the metabolic constraints in the production of bioethanol from lignocellulose-derived sugars by developing recombinant S. cerevisiae strains.     

Proteomics analysis of Bifidobacterium longum NCC2705 growing on glucose, fructose, mannose, xylose, ribose, and galactose

To investigate the molecular mechanisms underlying carbohydrate uptake and connected metabolic pathways of Bifidobacterium longum NCC2705, the proteomic profiles of bacteria grown on different carbon sources including glucose, fructose, mannose, xylose, ribose, and galactose were analyzed. Our results show that all sugars tested were catabolized via the bifid shunt. Sixty-eight proteins that exhibited changes in abundance of threefold or greater were identified by MS. A striking observation was the differential expression of proteins related to the pyruvate metabolism. Further analysis of acetic acid and lactic acid in the culture supernatants by HPLC at the end of fermentation showed that more lactic acid was produced during growth on fructose, ribose, xylose, galactose and more acetic acid was produced during the fermentation of glucose and mannose. Growth experiments revealed that B. longum NCC2705 preferentially used fructose, ribose, xylose, and galactose with higher growth rates over glucose and mannose. Furthermore, five proteins (GroEL, Eno, Tal, Pgm, and BL0033) exhibited clear phosphorylation modifications at serine and/or tyrosine residues. BL0033, a component of an ATP-binding cassette (ABC) transporter, was significantly more abundant in bacteria grown on fructose and, to a lesser extent, ribose and xylose. RT-PCR analysis revealed that all genes of the ABC transporter are induced in the presence of these sugars suggesting that BL0033, BL0034, BL0035, and BL0036 constitute an ABC transporter with fructose as preferred substrate.     

Carbon Source Requirements for Exopolysaccharide Production by Lactobacillus casei CG11 and Partial Structure Analysis of the Polymer

Exopolysaccharide production by Lactobacillus casei CG11 was studied in basal minimum medium containing various carbon sources (galactose, glucose, lactose, sucrose, maltose, melibiose) at concentrations of 2, 5, 10, and 20 g/liter. L. casei CG11 produced exopolysaccharides in basal minimum medium containing each of the sugars tested; lactose and galactose were the poorest carbon sources, and glucose was by far the most efficient carbon source. Sugar concentrations had a marked effect on polymer yield. Plasmid-cured Muc^- derivatives grew better in the presence of glucose and attained slightly higher populations than the wild-type strain. The values obtained with lactose were considerably lower for both growth and exopolysaccharide yield. The level of specific polymer production per cell obtained with glucose was distinctively lower for Muc^- derivatives than for the Muc⁺ strain. The polymer produced by L. casei CG11 in the presence of glucose was different from that formed in the presence of lactose. The polysaccharide produced by L. casei CG11 in basal minimum medium containing 20 g of glucose per liter had an intrinsic viscosity of 1.13 dl/g. It was rich in glucose (76%), which was present mostly as 2- or 3-linked residues along with some 2,3 doubly substituted glucose units, and in rhamnose (21%), which was present as 2-linked or terminal rhamnose; traces of mannose and galactose were also present.     

中性糖在土壤中的来源与分布特征

糖类(即碳水化合物)是土壤有机质的重要组成部分, 经生物化学降解形成不同结构的单糖。土壤中的中性单糖也叫中性糖, 主要包括木糖、核糖、阿拉伯糖、葡萄糖、半乳糖、甘露糖、岩藻糖和鼠李糖。其中, 植物来源的糖主要为五碳糖, 如木糖和阿拉伯糖; 微生物来源的糖主要包括半乳糖、甘露糖、岩藻糖、鼠李糖等六碳糖。研究中常利用六碳糖和五碳糖的比例指示微生物和植物对土壤有机碳的相对贡献。中性糖是微生物重要的碳源和能量来源, 在团聚体的形成过程中扮演着重要角色。该文整合了近30年土壤中性糖的研究进展, 对比了提取中性糖的常用方法, 分析了不同土地利用类型和不同土壤组分中中性糖的含量、来源和周转特征, 综述了影响中性糖含量和分布的主要环境因素。结果表明, 中性糖在耕地土壤中的绝对含量和相对含量均显著低于针叶林、阔叶林、草地和灌丛4种土地利用类型。(半乳糖+甘露糖)/(阿拉伯糖+木糖)(GM/AX)在不同土地利用间差异不显著, 而(鼠李糖+岩藻糖)/(阿拉伯糖+木糖)(RF/AX)则表明草地土壤中的微生物来源的中性糖含量高于针叶林和耕地。不同密度的土壤组分中, 轻质组分中中性糖的含量比重质组分高, 重质组分中微生物来源的中性糖较多; 就不同粒径(或团聚体)而言, 黏粒(或微团聚体)中微生物来源的中性糖含量更丰富。有关影响土壤中性糖含量和分布的因素的研究, 目前主要集中在人为活动(如耕种和放牧等), 而有关温度、降水等自然环境因素影响的研究较少。     

Bioconversion of lignocellulose-derived sugars to ethanol by engineered Saccharomyces cerevisiae

Lignocellulosic biomass from agricultural and agro-industrial residues represents one of the most important renewable resources that can be utilized for the biological production of ethanol. The yeast Saccharomyces cerevisiae is widely used for the commercial production of bioethanol from sucrose or starch-derived glucose. While glucose and other hexose sugars like galactose and mannose can be fermented to ethanol by S. cerevisiae, the major pentose sugars D-xylose and L-arabinose remain unutilized. Nevertheless, D-xylulose, the keto isomer of xylose, can be fermented slowly by the yeast and thus, the incorporation of functional routes for the conversion of xylose and arabinose to xylulose or xylulose-5-phosphate in Saccharomyces cerevisiae can help to improve the ethanol productivity and make the fermentation process more cost-effective. Other crucial bottlenecks in pentose fermentation include low activity of the pentose phosphate pathway enzymes and competitive inhibition of xylose and arabinose transport into the cell cytoplasm by glucose and other hexose sugars. Along with a brief introduction of the pretreatment of lignocellulose and detoxification of the hydrolysate, this review provides an updated overview of (a) the key steps involved in the uptake and metabolism of the hexose sugars: glucose, galactose, and mannose, together with the pentose sugars: xylose and arabinose, (b) various factors that play a major role in the efficient fermentation of pentose sugars along with hexose sugars, and (c) the approaches used to overcome the metabolic constraints in the production of bioethanol from lignocellulose-derived sugars by developing recombinant S. cerevisiae strains.     

Changes of monosaccharide availability of human hybridoma lead to alteration of biological properties of human monoclonal antibody

The effect of glucose and other monosaccharide availability in culture medium on production of antibody by human hybridomas has been studied. Human hybridoma cells C5TN produce an anti lung cancer human monoclonal antibody, and the light chain isN-glycosylated at the variable region. When the cell line was grown in the presence of various concentrations of glucose, the antibodies produced changed their antigen-binding activities. Analysis of the light chains produced under these condition revealed that four molecular-mass variant light chains ranging from about 26 to 32 kDa were secreted. The twenty six-kDa species, which corresponds to a non-glycosylated form of the light chain, was recovered after enzymatic removal of allN-linked carbohydrate chains, indicating that the source of the heterogenity of the light chain is due to the varied glycosylation. When the C5TN cells were cultured in medium containing either fructose, mannose or galactose instead of glucose, galactose elevated the antigen binding activity of the antibody more than the other sugars. These results suggest that change of glucose availability affects the antigen-binding activity of the antibodyvia the alteration of the glycosylation.