Seed flavonoids of thePodalyrieae andLiparieae (Fabaceae)

A study of the phenolic compounds of the closely related papilionoid tribes,Podalyrieae andLiparieae, proved that the flavonoid patterns of hydrolysed seed extracts are remarkably conservative. Butin (7, 3, 4-trihydroxyflavanone), 3-hydroxydaidzein (7, 3, 4-trihydroxyisoflavone), vicenin-2 (6, 8-di--D-glucopyranosyl-5, 7, 4-trihydroxyflavone) and orobol (5, 7, 3, 4-tetrahydroxyisoflavone) were isolated and identified as the major flavonoids. The seeds ofAmphithalea, Coelidium, Liparia, Xiphotheca, Calpurnia, Stirtonanthus andPodalyria accumulated three isoflavone O-glycosides that yielded 3-hydroxydaidzein on hydrolysis. In contrast,Virgilia contained a unique combination of vicenin-2 and orobol. Vicenin-2 was also present inCalpurnia as a major compound, butStirtonanthus insignis was the only other species studied that contained orobol (in trace amounts only). Butein, a chalcone, was reported byHarborne from the seed ofCyclopia subternata. This compound's flavanone analog, butin, was the principal component inCyclopia. A cladistic analysis, using flavonoid, alkaloid and morphological data, showed that the seed flavonoids of thePodalyrieae andLiparieae behave rather poorly as cladistic characters. They are, however, of considerable taxonomic value at the tribal level favouring the opinion that the two tribes should be combined. The apparent absence of flavonoids in the seed ofHypocalyptus supports the suggestion that it should be excluded from theLiparieae. Flavonoids also show that theArgyrolobium-group is very different from the tribeCrotalarieae and support the recent transfer of this group to the tribeGenisteae.     

Detection and partial characterization of two antigenically distinct β-amylases in developing kernels of wheat

A -amylase (EC 3.2.1.2) was identified in the outer pericarp (P) of developing seeds of wheat (Triticum aestivum L.) and compared with the well known -amylase which is synthesized during seed development in the starchy endosperm (E). The enzyme P already exists in the tissues before anthesis and vanishes at the time when E starts to accumulate. The isoelectric-focusing patterns of P and E are very similar. The relative molecular weight (M_r) of P is slightly higher than that of E (66 and 64.5 kDa, respectively). Both P and E exhibit common epitopes in addition to epitopes specific for each of them. The two enzymes were identified in small amounts in the green tissues of the developing seeds (inner pericarp and testa). No antigenic difference was detected between P and the -amylases of roots and leaves.Abbreviations P pericarp -amylase - E endosperm -amylase - IS1 anti--amylase immune serum - IS2 anti- and anti- amylase immune serum - IS3 anti- amylase immune serum - IEF isoelectric focusing - IgG immunoglobulin G The authors thank Dr. P. Ziegler (Universität Bayreuth, FRG) for stimulating discussion and for useful suggestions during the writing of the text. The authors thank Miss C. Mayer for her skillful technical assistance.     

Carbohydrates of influenza virus. Structure of the oligosaccharides linked to asparagines 406 and 478 in the hemagglutinin of fowl plague virus,strain dutch

Fowl plague virus, strain Dutch, was metabolically labeled withd-[2-³H]mannose, or withd-[6-³H]glucosamine, and the small subunit (HA₂; 0.8 mg in total) of the viral hemagglutinin was isolated by preparative sodium dodecylsulfate-polyacrylamide gel electrophoresis. After proteolytic digestion, the radioactive oligosaccharides were sequentially liberated from the glycopeptides by treatment with different endo--N-acetylglucosaminidases and with peptide:N-glycosidase or, finally, by hydrazinolysis. In this manner, four groups of glycans could be obtained by consecutive gel filtrations and were subfractionated by HPLC. The structures of the individual oligosaccharides were analyzed by micromethylation, by acetolysis or by digestion with exoglycosidases. The major species amongst the high mannose glycans at Ans-406 of the viral glycopolypeptide were found to be Man1-2Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNac1-4GlcNAc and Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNAc1-4GlcNAc, while the complex glycans at Asn-478 are predominantly GlcNAc1-2Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc (lacking, in part, one of the outerN-acetylglucosamine residues) and GlcNAc1-2Man1-3(Gal1-4GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc.Abbreviation BSA bovine serum albumin - endo D (F,H) endo--N-acetyl-d-glucosaminidase D (F,H) - HA hemagglutinin (HA₁, large subunit of HA - HA₂ small subunit - FPV fowl plague virus - PNGase F peptide:N-glycosidase F - SDS sodium dodecylsulfate     

Die Gattungsmerkmale vonSchizoboea (Gesneriaceae-Didymocarpeae)

The two characters used byBurtt (1974) to segregate the genusSchizoboea fromDidymocarpus, viz. terminal inflorescence and fruit splitting into 4 valves, have been studied in detail: (a) The terminal inflorescence represents a bracteate florescence (sensuTroll), that is an open thyrse, peculiar because of its only two extremely condensed internodes (basic internode + 1 following internode). Correspondingly, there are only two pairs of bracts from which the lower one only is capable to develop axillary partial florescences, i.e. pair-flowered cymes. Thus, the number of cymes is restricted to 2. Because of the condensed internodes, the inconspicuous bracts, and the densely aggregated flowers the two cymes simulate a unitary, terminal structure. By sympodial (± asymmetrically dichasial) linkage of shoot units, composed of an extended internode, a foliage leaf pair (from the axils of which the consecutive units arise) and the florescence,Schizoboea forms (polytelic) anthocladial shoot systems like some genera of the tribeKlugieae (incl.Loxonieae). (b) The fruit dehisces first loculicidally, then each valve splits into three portions (lateral rib and 2 semivalves). Moreover, the 4 placentae become isolated, thus the old fruit comprises 10 elements forming a loose fascicle.—The segregation ofSchizoboea fromDidymocarpus is supported. Whether the affinity is closer toSaintpaulia (as suspected byBurtt) ot toDidymocarpus, remains undecided: In regard to its shoot and inflorescence organization a morphological derivation is possible from both genera.

     

Theβ-subunit of human chorionic gonadotropin containsN-glycosidic trisialo tri- and tri′-antennary carbohydrate chains

TheN-linked carbohydrate chains of the-subunit of highly purified urinary human chorionic gonadotropin have been re-investigated. The oligosaccharides were released enzymatically by peptide-N ⁴-(N-acetyl--glucosaminyl)asparagine amidase-F, and fractionated by a combination of FPLC and HPLC. As a result of the application of improved fractionation methods, apart from the earlier reported carbohydrate chains, also small amounts of trisialo tri- and tri-antennary oligosaccharides were found. The primary structures of the latter carbohydrate chains have been determined by 500-MHz¹H-NMR spectroscopy to beAbbreviations hCG human chorionic gonadotropin - hCG- -subunit - hCG- -subunit - PNGase-F peptide-N ⁴-(N-acetyl--glucosaminyl)asparagine amidase-F (E.C. 3.5.1.52) - endo-F endo--N-acetylglucosaminidase-F (E.C. 3.2.1.96) - SDS sodium dodecyl sulphate - PAGE polyacrylamide gel electrophoresis - CBB coomassie brilliant blue R 250 - GlcNAc N-acetylglucosamine - NeuAc N-acetylneuraminic acid - Man mannose - Gal galactose - Fuc fucose     

Meiotic studies ofElymus nutans andE. jacquemontii (Poaceae,Triticeae) and their hybrids withPseudoroegneria spicata and seventeenElymus species

Hybridizations ofElymus nutans andE. jacquemontii were carried out with one species ofPseudoroegneria (S genome), and 20Elymus species, each containing either of the SH, SY, SYH, or SYW genomes. Chromosome configurations were analysed at metaphase I of the two target taxa and their interspecific hybrids. It is concluded that (i)E. nutans is an allohexaploid containing the SYH genomes, andE. jacquemontii is an allotetraploid having the SY genomes; (ii) the genomic affinity is associated with the geographic distance between the species studied; (iii) minor genomic structural rearrangements have occurred within the hexaploid taxon ofE. nutans.     

Microbial transformation of ginsenoside Rb1 by Rhizopus stolonifer and Curvularia lunata

Of 49 microbial strains screened for their capabilities to transform ginsenoside Rb₁, Rhizopus stolonifer and Curvularia lunata produced four key metabolites: 3-O-[-d-glucopyranosyl-(1,2)--d-glucopyranosyl]- 20-O-[-d-glucopyranosyl]-3,12, 20(S)-trihydroxydammar-24-ene (1), 3-O-[-d-glucopyranosyl-(1,2)--d- glucopyranosyl]-20-O-[-d-glucopyranosyl]-3,12, 20(S)-trihydroxydammar-24-ol (2), 3-O-[-d-gluco- pyranosyl-(1,2)--d-glucopyranosyl]-3, 12, 20(S)-trihydroxydammar-24-ene (3), and 3-O--d-glucopyranosyl-3, 12, 20(S)-trihydroxydammar-24-ene (4), identified by TOF-MS, ¹H- and ¹³C-NMR spectral data. Metabolites 1, 3 and 4 were from the incubation with R. stolonifer, and 1 and 2 from the incubation with C. lunata. Compound 2 was identified as a new compound.     

Effect of α(2–6)-linked sialic acid and α(1–3)-linked fucose on the interaction ofN-linked glycopeptides and related oligosaccharides with immobilizedPhaseolus vulgaris leukoagglutinating lectin (L-PHA)

The effects of branching and substitution of branches by sialic acid and fucose on the interaction ofN-linked glycopeptides and related oligosaccharides with immobilizedPhaseolus vulgaris leukoagglutinating lectin (L-PHA) were examined. Asialo bi-, tri-and tetra-antennary glycans were all retarded but to different extents on a long column of L-PHA-agarose. Asialo tri- and tetra-antennary glycans containing the pentasaccharide unit Gal1-4GlcNAc1-2[Gal1-4GlcNAc1-6]Man were strongly retarded, whereas asialo bi- and tri-antennary glycans lacking the Gal1-4GlcNAc1-6 branch were only weakly retarded. In all instances the interaction with the lectin was completely abolished when either (2–6)-linkedN-acetylneuraminic acid or (1–3)-linked fucose was present at the galactose orN-acetylglucosamine residue of the Gal1-4GlcNAc1-6Man1-6 branch, respectively. The same substitutions on the Gal1-4GlcNAc1-6Man1-6 branch decreased but did not abolish the affinity of the lectin for the glycans. The presence of NeuAc2-6 and Fuc1-3 on the other two branches did not interfere with the binding of the glycans to L-PHA. Furthermore, it appeared that the presence of the Man1-4GlcNAc unit is requried for interaction with the lectin. In order to obtain reliable information on the relative occurrence of tri- and tetra-antennary glycopeptides, this study shows that it is essential to desialylate and to defucosylate the glycans prior to application to L-PHA-agarose.Abbreviations L-PHA leukoagglutinating phytohemagglutinin - CMP-NeuAc cytidine-5-monophospho-N-acetylneuraminic acid - GP glycopeptide - OS oligosaccharide - HPLC high-performance liquid chromatography - FNR fraction not retarded - FR fraction retarded suffixes MS, BS and TS indicate mono-, bi- and trisialyl derivatives respectively; suffix MF indicates monofucosyl derivatives.structures of the substratesOS2, OS3, OS3, OS4, GP2, GP3, GP4, GP4-MF, OS2(3) andOS2(-) are presented in Fig. 2     

Lysine Dendrimers and Their Starburst Polymer Derivatives: Possible Application for DNA Compaction and in vitro Delivery of Genetic Constructs

We attempted to find some compounds for the effective delivery of gene constructs into cells and obtained two trispherical dendrimers on the basis of lysine, (Lys)₈-(,-Lys)₄-(,-Lys)₂-(,-Lys)-Ala-NH₂ (D1) and ((Lys)₈-(,-Lys)₄-(,-Lys)₂-,-Lys)-Ala-[Lys(Plm)]₂-Ala-NH₂ (D2), as well as the starburst polymeric derivatives of D1, (pVIm) ₈ -D1 and (pLys) _n -D1, containing poly(N-vinylimidazole) and polylysine chains single-point bound to the dendrimer amino groups. The conditions of dendrimer–plasmid DNA complex formation were studied. The intracellular localization of these complexes and the expression of gene constructs delivered with their help were analyzed in transfection experiments on the HeLa cell cultures of human epithelial carcinoma and on mouse C2C12 myoblasts. It was found that the chemical structure of dendrimer D1 and its derivatives significantly affected the structure and properties of complex.     

Agrobacterium-mediated transformation of white clover using direct shoot organogenesis

Summary White clover (Trifolium repens L.) plants from the cultivars Grasslands Huia and Grasslands Tahora have been transformed using Agrobacterium-mediated T-DNA transfer. Transgenic plants regenerated directly from cells of the cotyledonary axil. To transform white clover, shoot tips from 3 day old seedlings were co-cultivated with A. tumefaciens strain LBA4404 carrying the plasmid vector pPE64. This vector contains the neomycin phosphotransferase II gene (nptII) and -glucuronidase reporter gene (gus) both under the control of the CaMV 35S promoter. Kanamycin-resistant plants regenerated within 42 days after transfer onto selective media. Integration of the nptII and gus genes into the white clover genome was confirmed using Southern blotting, and histochemical analysis indicated that the gus gene was expressed in a variety of tissues. In reciprocal crosses between a primary transformant and a non-transformed plant the introduced gus gene segregated as a single dominant Mendelian trait.Abbreviations BAP 6-benzylaminopurine - NAA -naphthaleneacetic acid - MS Murashige and Skoog - GUS -glucuronidase - X-GLUc 5-bromo-4-chloro-3-indolyl--D-glucuronide - MUG methylumbelliferyl--D-glucuronide - CaMV Cauliflower Mosaic Virus - NPTII neomycin phosphotransferase II - OCS octopine synthase - 4-MU 4-methyl umbelliferone     

Immunosystematical comparison ofPhaseolus coccineus seed proteins with those of other legumes

An immunosystematical research was conducted on the seed proteins of 32 species ofFabaceae. By comparing all immunelectrophoretic patterns with the self reaction of a reference system (Phaseolus coccineus) all proteins detected have been identified and their distribution within the family has been analyzed. Half of the proteins identified inP. coccineus gave positive cross reactions with proteins present in all other species. Among this group are protein I and phaseolin. This result supports the homologization between phaseolin and vicilin. Among the other proteins, three are irregularly distributed throughout the family, and only three are restricted to a few taxa. This last group includes phytohaemagglutinin, which does not present any cross reaction outside the tribePhaseoleae.     

Increased taxane accumulation in callus cultures of Taxus cuspidata and Taxus × media by some elicitors and precursors

In Taxus cuspidata callus, vanadyl sulfate (10 mg l^–1) induced a high (146 g g^–1 dry wt) production of 10-deacetylbaccatin III in comparison to 7 g g^–1 dry wt of the control. The content of paclitaxel in this species increased from 16 g g^–1 to 74 g g^–1 dry wt when 20 mg phenylalanine l^–1 was used. In T. media, p-aminobenzoic acid induced the highest content of 10-deacetylbaccatin III (481 g g^–1 dry wt) versus 181 g g^–1 in the control. Paclitaxel increased from 89 to 139 g g^–1 dry wt after adding chitosan (20 mg l^–1) to the cultures.     

β-Carotene synthesis in isolated chromoplasts from Narcissus pseudonarcissus

A system has been established from isolated intact chromoplasts of Narcissus pseudonarcissus flowers that synthesizes geranylgeraniol, an unknown polyprenoid alcohol, phytoene, and -carotene from [1-¹⁴C]isopentenyl pyrophosphate in a good yeild. Long chain pyrophosphates are not accumulated. San 6706 inhibits the dehydrogenation of phytoene, whereas nicotine does not lead to an accumulation of lycopene. Separation and identification of polyprenoid lipids was performed by HPLC. The properties and advantages of the chromoplast system are discussed.Abbreviations IPP isopentenyl pyrophosphate - TLC thin-layer chromatography - HPLC high pressure liquid chromatography - GC gas chromatography - Sau 6706 4-chloro-5-(dimethylamino)-2-,,-(trifluoro-m-tolyl)3(2H)-pyridazinone     

Growth,acetylene reduction activity and localization of nitrogenase in relation to vesicle formation in Frankia strains Cc1.17 and Cp1.2

A comparative study was conducted on the effect of NH₄Cl on growth, vesicle formation and formation of nitrogenase of Frankia strains Cc1.17 and Cp1.2, derived from root nodules of Colletia cruciata and Comptonia peregrina, respectively. On a medium without combined nitrogen (P-N), both strains formed spherical cells, called vesicles, like many other Frankia strains. Data are presented on the number of vesicles per mg protein, after cultivation in media with sodium propionate as C-source without combined nitrogen (P-N) or with 0.2 g NH₄Cl/l (P+N). Strain Cp1.2 as may other Frankia strains, showed on P+N medium a very strong reduction of vesicle formation of 99% relative to the number of vesicles formed on P-N medium, after 11 days growth. However, in strain Cc11.17 this reduction was only 70%. The occurence of relatively large numbers of vesicles in P+N media has not yet been reported for other Frankia strains. No acetylene reduction activity was found in NH ₄ ⁺ -grown cells. The regulation of induction of nitrogenase in Frankia by NH₄Cl was tested by immuno-gelectrophoresis using antisera against nitrogenase of Rhizobium leguminosarum PRE. The component I of the enzyme showed crossreactivity while the component II had only a weak crossreaction. The experiments indicated that no nitrogenase was detectable in the NH ₄ ⁺ -grown cells. For the localization of nitrogenase, relative amounts of the enzyme were compared in whole cells and vesicle-enriched fractions. Western blots showed a significant enrichment of nitrogenase in the vesicle fractions, which indicated that most of the nitrogenase was localized in the vesicle.     

In vitro plant regeneration via somatic embryogenesis from root culture of some rhizomatous irises

A method for plant regeneration of Iris via somatic embryogenesis is described. Root and leaf pieces from in vitro-grown plants of several genotypes of rhizomatous Iris sp. were cultured in vitro. Callus induction occurred only on root cultures incubated under low light intensity (35 mol m^-2 s^-1) on two induction media containing 2,4-D (4.5 or 22.5 M), NAA (5.4 M) and kinetin (0.5 M). Somatic embryos developed after transfer of callus onto four regeneration media containing 9 or 22 M BA, or 5 M kinetin and 2 M TIBA or 9 M BA and 4 M TIBA. Plantlets could be obtained from these somatic embryos. Genotypic differences were found both in callus induction and somatic embryo formation, with I. pseudacorus responding better than I. versicolor or I. setosa. Cytological analysis performed on root tips of 80 regenerated plants revealed that two of the I. pseudacorus regenerants were tetraploid.Abbreviations 2,4-D dichlorophenoxy acetic acid - NAA naphthaleneacetic acid - BA 6-benzyladenine - TIBA 2,3,5-triiodobenzoic acid - IBA indolebutyric acid     

Reconstitution of cytoplasmic streaming inCharaceae

Summary The active sites of actin of oneCharaceae species were found to interact with the endoplasmic factor from a different species. Protoplasm was suqueezed out of cells ofChara australis with vacuoles that had been perfused beforehand with a medium containing EGTA and Mg · ATP. Centrifugation of this protoplasmic mixture divided it into the supernatant composed of endoplasmic granules and the precipitate composed of chloroplasts and nuclei. When the endoplasmic granular aggregates were introduced into a tonoplast-freeNitella axilliformis cell treated with NEM to inactivate the endoplasmic factor, they became attached to theNitella gel and streamed longitudinally with the polarity. Treatment of the endoplasmic granules with the strong Mg²⁺chelator CyDTA (1,2-cyclohexane diamineN, N-tetraacetic acid) irreversibly inhibited reconstitution of the cytoplasmic streaming.Abbreviations APW artificial pond water - ATP adenosine-5-triphosphoric acid - CyDTA cyclohexanediamine-N,N-tetraacetic acid - DTT dithiothreitol - EGTA ethyleneglycol-bis-(-aminoethylether)-N,N-tetraacetic acid - HMM heavy meromyosin - NEM N-ethylmaleimide - PEP phosphoenolypyruvate - PIPES piperazine-N,N-bis-(2-ethane-sulfonic acid) - PK pyruvate kinase - PMSF phenylmethylsulfonylfluoride     

Variability in the 11S globulin fraction of seed storage proteins ofHelianthus (Asteraceae)

The seed storage globulins from sixHelianthus and four hybrids were studied using mono and bidimensional gel SDS electrophoresis (+ 2 mercaptoethanol). The polypeptide composition of each subunit was determined. Different pairs are specifically expressed according to the species studied. Three typical patterns were discriminated. All the studied species exhibit five subunits: two of them are expressed in all the species (₁₁ and ₂₂). The subunit corresponding to the ₁₁ pair is present inH. petiolaris and in the three populations ofH. annuus studied. The _2b2 pair is common toH. annuus andH. argophyllus. H. petiolaris presents two specific _2a2 and ₄₄ pairs andH. annuus a specific ₃₃ pair. InH. argophyllus _{11 33} or ₄₄ are never observed but are replaced by ₁₃ and ₃₁ pairs. Some globulins, poorly represented, are of forms but present chains of higher molecular weights (in the range 54–56 kDa). Expressing variations in the banding patterns between these species by the use of a similarity index reveals complete identity between the three populations ofH. annuus. Identity between the twoH. petiolaris studied is also observed.H. annuus andH. argophyllus appear to be closer to each other thanH. petiolaris concerning the seed storage globulins.     

Effect of microrelief and vegetation on methane emission from wet polygonal tundra, Lena Delta, Northern Siberia

The effect of microrelief and vegetation on methane (CH₄) emission was investigated in a wet polygonal tundra of the Lena Delta, Northern Siberia (72.37N, 126.47E). Total and plant-mediated CH₄ fluxes were measured by closed-chamber techniques at two typical sites within a low-centred polygon. During the study period, total CH₄ flux averaged 28.0±5.4mgm^–2d^–1 in the depressed polygon centre and only 4.3±0.8mgm^–2d^–1 at the elevated polygon rim. This substantial small-scale spatial variability of CH₄ emission was caused by strong differences of hydrologic conditions within the microrelief of the polygon, which affected aeration status and organic matter content of the soils as well as the vegetation cover. Beside water table position, the vegetation cover was a major factor controlling CH₄ emission from polygonal tundra. It was shown that the dominant vascular plant of the study area, Carex aquatilis, possesses large aerenchyma, which serve as pathways for substantial plant-mediated CH₄ transport. The importance of plant-mediated CH₄ flux was strongly influenced by the position of the water table relative to the main root horizon. Plant-mediated CH₄ transport accounted for about two-thirds of the total flux in the wet polygon centre and for less than one-third of the total flux at the moist polygon rim. A clipping experiment and microscopic-anatomical studies suggested that plant-mediated CH₄ transport via C. aquatilis plants is driven only by diffusion and is limited by the high diffusion resistance of the dense root exodermes.     

The genetics of adult-plant blackleg (Leptosphaeria maculans) resistance from Brassica juncea in B. napus

The genetic control of adult-plant blackleg (Leptosphaeria maculans) resistance in a Brassica napus line (579NO48-109-DG-1589), designated R13 possessing Brassica juncea-like resistance (JR), was elucidated by the analysis of segregation ratios in F₂ and F₃ populations from a cross between R13 and the highly blackleg-susceptible B. napus cultivar Tower. The F₂ segregration ratios were bimodal, demonstrating that blackleg resistance in R13 was controlled by major genes. Analysis of the segregation ratios for 13 F₃ families indicated that blackleg resistance in these families was controlled by three nuclear genes, which exhibited a complex interaction. Randomly sampled plants of F₃ progeny all had the normal diploid somatic chromosome number for B. napus. The similarities between the action of the three genes found in this study with those controlling blackleg resistance in B. juncea is discussed.     

Sialyltransferases of developing rat brain

The activity of four different sialyltransferases acting on N- or O-linked chains of glycoproteins was studied in brains of 19 days-old embryos, 1 day-old newborns and adult rats. By using asialofetuin, fetuin andN-acetyllactosamine as acceptors, it has been possible to measure independently the following enzyme activities: CMP-NeuAc:Gal1-3GalNac (2–3)-sialyltransferase (EC 2.4.99.4), CMP-NeuAc:Gal1-4GlcNAc (2–3)-sialyltransferase (EC 2.4.99.6), CMP-NeuAc:Gal1-4GlcNAc (2–6)-sialyltransferase (EC 2.4.99.1) and CMP-NeuAc:NeuAc2-3Gal1-3GalNac (2–6)-sialyltransferase (EC 2.4.99.7). The specific activity of the first three enzymes which act on asialylated acceptors showed a 2.6-fold decrease in a parallel manner after ontogenic development, while the activity of NeuAc2-3Gal1-3GalNac (2–6)-sialyltransferase was four times lower in adult than in embryonic brain, showing a stronger dependence on ontogenic development. Despite the higher level of sialyltransferases able to act on glycoproteins, in fetal brain these glycoproteins do not contain a higher amount of sialic acid.Abbreviations HPLC high performance liquid chromatography - N-CAM neural cell adhesion molecule