作者索引

二.丁光生(兑曹衍霖丁光生)···································································一(60,67) 丁光生(兑林吉强等)..············································································……(249) 丁光生(兑朱巧真丁光生)..······························································…     

《古生物学报》第12卷1964总目录

吉林及黑龙江白奎耙新叶肢介化石···································4·································……张文堂、陈玉基(1)湖北长阳上泥盆抗写握寺粗中的几个苔藤虫·····································································……惕敬之(26)贵州独山、都匀等地中、上泥盆扰中的介形类·········································…     

广西植物 第十二卷 总目录

第一期(1992年2月)壳斗科植物摘录(V)········································································……黄成就张永田(】)马兜铃属一新植物·························································,············,···················……余伟(3)含笑属一新变种············,····························…     

生理学报第55卷(继续《中国生理学杂志》1927年创刊)总目次

第一期编者的话·····,···,···.··········..··,··,····,,····,·······················、·········································,·············……姚泰(i》投稿须知·····································································································,···············…     

《生理科学进展》1987年第18卷分类索引

生理学 新的前景新的期望韩济生18(l):1一个生理学工作者的三愿················……,’’·····,···········,·…,’’······················……吴襄18(1):2迎来科学的春天························································,·,·························……工志均18(l):8科研工作贵在坚持···········································…     

应用生态学报第3卷(1992)作者索引

二西丁武李阜棣:根瘤菌生态学研究中两个数学模型的探讨································……,’’····……3(2):173丁瑞兴黄晓澜周亚军:茶园间植乌柏的气候生态效应················································……3(2):131 三画于殿臣(见张丽珊卜··························································································…     

水生生物学集刊 1956年 总目录

第期青焦赤皮病致病菌的初步研究········“·············~···············································……王德络(1〕青、脱、墉、醚等家焦寄生原生勤物的研究.11.寄生青焦的原生虱物···~················……陈件玺(19)束旗湖的枝角颊···································”·,··································,···············……集希珠(43)江…     

生物工程进展第13卷(1993年)总目录

第l期研究进展组织皿纤溶醉原激活因子的分子生物学研究进展··················”···、······································..·····……“房健兴般城(l)Ti质拉T区基因转移与整合分子机制的研究进展·····················································,···……“··….族胶许组(5》酿酒醉母工程菌研究进展·············································…     

生理学报第45卷作者索引

‘】咚。凡佩·r,、l黔.11\r见食孝如等)·····················,·······,··························4···········,························……(528。钧叭闹卜.川、目rd(’尼阴伟真等)····,···············,·······························,···········································……(20川M.山门J.、.L叩、、l}‘见tIl伟真等)···…     

植物生态学与地植物学学报第17卷总目录

第1期(1993年1月)河西走廊芦苇的光合碳同化途径对生境条件的适应·································……郑学平张承烈陈国仓(1)秦岭南坡旬河流域森林植被生态种组的初步研究···························································……康慕谊(9)2500。年以来渤海湾西岸古环境探讨·····························,·········································……     

A critical evaluation of neoglycoprotein binding sites in vivo and in sections of mouse tissues.

Endogenous lectins are reported to play a vital role in cell to cell communication. Their distribution in tissues has been widely studied by the use of labelled neoglycoproteins. In the present study, labelled neoglycoproteins were used on fixed and unfixed tissue sections and the results were compared with those observed after i.v. application of neoglycoproteins in mice. The study indicates that neoglycoprotein binding to tissue sections is not inhibited by application of the simple monosaccharides that were used to synthesize them. Furthermore the binding of neoglycoproteins following i.v. application into mice is rather limited. It is concluded that neoglycoproteins, which are synthesized using simple monosaccharides, do not provide a sensible tool to detect endogenous lectins in animal tissue sections. This is in sharp contrast to the results of most other studies reported in the literature.     

A critical evaluation of neoglycoprotein binding sites in vivo and in sections of mouse tissues

Summary Endogenous lectins are reported to play a vital role in cell to cell communication. Their distribution in tissues has been widely studied by the use of labelled neoglycoproteins. In the present study, labelled neoglycoproteins were used on fixed and unfixed tissue sections and the results were compared with those observed after i.v. application of neoglycoproteins in mice. The study indicates that neoglycoprotein binding to tissue sections is not inhibited by application of the simple monosaccharides that were used to synthesize them. Furthermore the binding of neoglycoproteins following i.v. application into mice is rather limited. It is concluded that neoglycoproteins, which are synthesized using simple monosaccharides, do not provide a sensible tool to detect endogeneous lectins in animal tissue sections. This is in sharp contrast to the results of most other studies reported in the literature.     

Determination of modulation of ligand properties of synthetic complex-type biantennary N-glycans by introduction of bisecting GlcNAc in silico, in vitro and in vivo.

We have investigated the consequences of introducing a bisecting GlcNAc moiety into biantennary N-glycans. Computational analysis of glycan conformation with prolonged simulation periods in vacuo and in a solvent box revealed two main effects: backfolding of the alpha1-6 arm and stacking of the bisecting GlcNAc and the neighboring Man/GlcNAc residues of both antennae. Chemoenzymatic synthesis produced the bisecting biantennary decasaccharide N-glycan and its alpha2-3(6)-sialylated variants. They were conjugated to BSA to probe the ligand properties of N-glycans with bisecting GlcNAc. To assess affinity alterations in glycan binding to receptors, testing was performed with purified lectins, cultured cells, tissue sections and animals. The panel of lectins, including an adhesion/growth-regulatory galectin, revealed up to a sixfold difference in affinity constants for these neoglycoproteins relative to data on the unsubstituted glycans reported previously [André, S., Unverzagt, C., Kojima, S., Dong, X., Fink, C., Kayser, K. & Gabius, H.-J. (1997) Bioconjugate Chem. 8, 845-855]. The enhanced affinity for galectin-1 is in accord with the increased percentage of cell positivity in cytofluorimetric and histochemical analysis of carbohydrate-dependent binding of labeled neoglycoproteins to cultured tumor cells and routinely processed lung cancer sections. Intravenous injection of iodinated neoglycoproteins carrying galactose-terminated N-glycans into mice revealed the highest uptake in liver and spleen for the bisecting compound compared with the unsubstituted or core-fucosylated N-glycans. Thus, this substitution modulates ligand properties in interactions with lectins, a key finding of this report. Synthetic glycan tailoring provides a versatile approach to the preparation of newly substituted glycans with favorable ligand properties for medical applications.     

Tissue distribution of radioiodinated neoglycoproteins and mammalian lectins

Quantitation of tissue distribution of radioiodinated neoglycoproteins 1 h after intravenous injection into mice allowed to evaluate their suitability to uncover potential selectivity in tracer retention. Variations within the panel of neoglycoproteins were introduced to the carbohydrate determinant, its density and linkage to the carrier. Five arrays of neoglycoproteins, encompassing up to twelve different carbohydrate moieties were used. The individual response on the level of organ content showed differences, accounted for by carbohydrate structure and density. However, increase in sugar density eventually caused general decrease in tissue retention, emphasizing the importance of synthetic parameters. Attachment of sugar residues to the spacer via primarily the C-6 group of monosaccharides led to rather prolonged survival in circulation of the resulting neoglycoprotein compared to the application of neoglycoproteins with p-aminophenyl glycosides as derivatives for coupling. Besides applying neoglycoproteins tissue uptake was also measured for several organs, when four mammalian lectins were employed as radiotracers. These lectins bind to cellular carbohydrate ligands, namely beta-galactosides, alpha-fucosides or heparin. Differences were measured for retention in liver, kidneys, spleen, stomach, thymus and bone marrow. The distinct properties of different tissues with respect to binding of neoglycoproteins as well as to endogenous lectins, exhibiting a certain degree of selectivity, are a step within the framework to attempt to therapeutically exploit the carrier potential of probes by recognitive protein-carbohydrate interactions.     

Quantum-dye labeled proteins for glycobiology: a viable nonradioactive alternative tracer

Quantum dye (QD), a macrocyclic europium-chelate, developed as a cytological marker, has never been used for quantitative applications. It would be ideal, however, if the same tracer can be used for both qualitative and quantitative purposes. We have labeled some lectins and neoglycoproteins with QD for the purpose of quantitative analyses in glycobiology, and tested its suitability in three different areas in glycobiology: (1) glycosyltransferase, (2) an animal lectin - mannose- binding protein, and (3) the Gal/GalNAc receptor of rat liver membrane. Usefulness of QD-labeled lectins was amply demonstrated by the quantification of galactosyltransferase activity using QD-soybean agglutinin and QD-RCA120 ( Ricinus communis agglutinin). We also showed that QD-labeled neoglycoproteins, QD-Man-BSA and QD-Gal-BSA, can replace radioiodinated counterparts in the binding assays of animal lectins (serum mannose binding protein and hepatic Gal/GalNAc receptor.) The advantage of QD and other europium labels is that it does not decay as radioiodides do. The long shelf-life results in more consistent results from repeated experiments.      

Detection of sugar-binding proteins in membrane-depleted nuclei

Nuclear sugar-binding proteins were detected in membrane-depleted nuclei isolated from hamster BHK cells and mouse L 1210 leukemia cells by means of fluorescein-labelled neoglycoproteins. In fluorescence microscopy, the fluorescence was seen throughout the nucleus but was generally brighter over the nucleoli than over the rest of the nucleus. Flow cytofluorometry analysis demonstrated the presence of nuclear sugar-binding proteins for synthetic glycoproteins associated with different sugar residues. Among the nine neoglycoproteins used, four neoglycoproteins (namely alpha-rhamnosylated, alpha-glucosylated, N-acetyl-beta-glucosaminylated and alpha-mannosylated-6P-serum albumin) strongly labelled nuclei. Various controls strongly argue for the specificity of the nuclear labelling. The possibility that some of the sugar-binding proteins might correspond to endogenous nuclear lectins is considered.     

Cell-Surface Lectins of Azospirillum spp.

Cell-surface lectins were screened in seven strains of Azospirillum brasilense and A. lipoferum. The presence of lectins was determined by particle agglutination assays employing latex beads coated with neoglycoproteins and by Western blot with neoglycoproteins labeled with horseradish peroxidase as a probe. Seven strains were agglutinated with the assayed sugar residues. The highest agglutination was with fucose and glucose and to a lesser extent with mannose residues. Cell-wall proteins extracted from two Azospirillum spp. strains exhibit lectin-like activities. We believe that lectins are present in the cell-wall of Azospirillum spp. Received: 23 June 1997 / Accepted: 23 September 1997     

Human keratinocyte membrane lectins: characterization and modulation of their expression by cytokines

Summary— In an attempt to identify cell surface molecules involved in recognition phenomena between cells such as keratinocytes and melanocytes and putatively target biological responses modifiers to keratinocytes, we undertook the detection of cell surface sugar specific receptors: membrane lectins. Keratinocyte membrane lectins were found to bind synthetic glycoproteins (neoglycoproteins) carrying either α-l -fucosyl or α-l -rhamnosyl residues. Fluorescence microscopy observations indicate that cultured keratinocytes are able to bind these two neoglycoproteins while frozen sections of human skin labelled with neoglycoprotein-coated covaspheres show that the selectivity of the binding to keratinocytes is restricted to α-l -rhamnosyl-BSA. Keratinocytes were adapted to grow on collagen; harvesting conditions allowing the analysis of keratinocytes by flow cytometry are described. This technique allows the quantification of the binding at 4°C, and the estimation of the endocytosis of F-, neoglycoproteins: F-, α-l -Rha-BSA and F-, α-l -Fuc-BSA were efficiently internalized. Thereafter, α-l -rhamnose-substituted liposomes containing 5-(6)carboxyfluorescein were prepared in order to follow the delivery of the fluorescent dye into cells. This was measured both by flow cytometry and by spectrofluorimetry. The expression of surface lectins was checked upon action of cytokines (IL₁α, IL₁β, IL₂ and TNF) which are known as biological response modifiers of keratinocytes.     

Influence of type of linkage and spacer on the interaction of beta-galactoside-binding proteins with immobilized affinity ligands

Affinity chromatography provides a powerful tool for isolation of carbohydrate-binding proteins. However, the choice of the ligand and spacer has an important impact on effectiveness. The influence of several different ligands on qualitative and quantitative aspects of the purification of two beta-galactoside-specific lectins has been evaluated. Sepharose was modified by coupling four types of neoglycoproteins (galactosylated or lactosylated bovine serum albumin with increasing sugar content) and two naturally occurring asialoglycoproteins at similar densities. Carbohydrate ligands at essentially equal density were made accessible to the lectins by seven commonly used methods. The yield of mistletoe lectin was high when lactosylated neoglycoproteins were used for separation. For these resins the sugar incorporation exceeded 10 sugar groups per protein carrier molecule. The yield was similarly high with the asialoglycoproteins and with lactose; the sugar was coupled to the resin as a p-aminophenyl derivative or by means of divinyl sulfone activation. An epoxy group in linkages of galactose or lactose decreased the binding capacity. A quantitatively similar degree of protein yields was obtained for the beta-galactoside-binding protein of bovine heart, although different proteins were obtained when neoglycoproteins were used as ligand. The nature of the affinity ligand in lectin purification can increase the yield and may also influence the profile of the carbohydrate-binding proteins.     

Characterization and biological implications of membrane lectins in tumor, lymphoid and myeloid cells

Complex carbohydrates and sugar receptors at the surface of eukaryotic cells are involved in recognition phenomena. Membrane lectins have been characterized, using biochemical, biological and cytological methods. Their biological activities have been assessed using labeled glycoproteins or neoglycoproteins. Specific glycoproteins or neoglycoproteins have been used to inhibit their binding capacity in both in vitro and in vivo experiments. In adults, lymphoid and myeloid cells as well as tumor cells grow in a given organ and eventually migrate and home in another organ; these phenomena are known as the homing process or metastasis, respectively. In specific cases, membrane lectins of endothelial cells recognize cell surface glycoconjugates of lymphocytes or tumor cells, while membrane lectins of lymphocytes and of tumor cells recognize glycoconjugates of extracellular matrices or of non-migrating cells. Therefore, membrane lectins are involved in cell-cell recognition phenomena. Membrane lectins are also involved in endocytosis and intracellular traffic of glycoconjugates. This property has been demonstrated not only in hepatocytes, fibroblasts, macrophages and histiocytes but also in tumor cells, monocytes, thyrocytes, etc. Upon endocytosis, membrane lectins are present in endosomes, whose luminal pH rapidly decreases. In cells such as tumor cells or macrophages, endosomes fuse with lysosomes; it is therefore possible to target cytotoxic drugs or activators, by binding them to specific glycoconjugates or neoglycoproteins through a linkage specifically hydrolyzed by lysosomal enzymes. In cells such as monocytes, the delivery of glycoconjugates to lysosomes is not active; in this case, it would be preferable to use an acid-labile linkage. Cell surface membrane lectins are developmentally regulated; they are present at given stages of differentiation and of malignant transformation. Cell surface membrane lectins usually bind glycoconjugates at neutral pH but not in acidic medium: their ligand is released in acidic specialized organelles; the internalized ligand may be then delivered into lysosomes, while the membrane lectin is recycled. Some membrane lectins, however, do bind their ligand in relatively acidic medium as in the case of thyrocytes. The presence of cell surface membrane lectins which recognize specific sugar moieties opens the way to interesting applications: for instance, isolation of cell subpopulations such as human suppressor T cells, targeting of anti-tumor or anti-viral drugs, targeting of immunomodulators or biological response modifiers.