Effect of thidiazuron on vegetative tissue-derived somatic embryogenesis and flowering of bamboo Bambusa edulis

Current research on somatic embryogenesis of bamboo uses reproductive tissue as explants. However, it was hard to obtain the explant. Shoots of a local accession (3–4 m high) were used for multiple shoot production. In order to obtain embryogenic callus, nodal and internodal tissues from in vitro plantlets were placed on Murashige and Skoog (MS) medium supplemented with 9.2 M kinetin (KN), 13.6 M 2,4-dichlorophenoxyacetic acid (2,4-D), 0.1% (v/v) coconut milk, and 6% (w/v) sucrose. We studied the effects of sucrose and thidiazuron (TDZ) on callus proliferation. Optimal additives to the MS medium for embryogenic callus proliferation were 0.046 M TDZ, 13.6 M 2,4-D and 3% (w/v) sucrose. TDZ also promoted the germination of bamboo somatic embryos. The germination rate of the somatic embryos exceeded 80% on MS-based medium supplemented with 0.455M TDZ. Naphthaleneacetic acid (NAA) reduced germination. Well-developed plantlets were successfully transferred to soil. There was no albino mutant in subsequent culture. In vitro regenerants and potted plants flowered, but no seeds were produced.     

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     

The effect of humidity and light on cellular water relations and diffusion conductance of leaves ofTradescantia virginiana L.

Turgor (_p) and osmotic potential (_s) in epidermal and mesophyll cells, in-situ xylem water potential (-xyl) and gas exchange were measured during changes of air humidity and light in leaves ofTradescantia virginiana L., Turgor of single cells was determined using the pressure probe. Sap of individual cells was collected with the probe for measuring the freezing-point depression in a nanoliter osmometer. Turgor pressure was by 0.2 to 0.4 MPa larger in mesophyll cells than in epidermal cells. A water-potential gradient, which was dependent on the rate of transpiration, was found between epidermis and mesophyll and between tip and base of the test leaf. Step changes of humidity or light resulted in changes of epidermal and mesophyll turgor (_p-epi, _p-mes) and could be correlated with the transpiration rate. Osmotic potential was not affected by a step change of humidity or light. For the humidity-step experiments, stomatal conductance (g) increased with increasing epidermal turgor.g/_p-epi appeared to be constant over a wide range of epidermal turgor pressures. In light-step experiments this type of response was not found and stomatal conductance could increase while epidermal turgor decreased.Symbols E transpiration - g leaf conductance - w leaf/air vapour concentration difference - -epi water potential of epidermal cells - -mes water potential of mesophyll cells - -xyl water potential of xylem - _p-epi turgor pressure of epidermal cells - _p-mes turgor pressure of mesophyll cells - _s-epi osmotic potential of epidermal cells - _s-mes osmotic potential of mesophyll cells     

Effect of light on the nucleotide composition of rRNA of wheat seedlings

Both qualitative and quantitative differences in the minor nucleotide constituents of rRNA from normally grown and from etiolated wheat plants (Triticum aestivum L.) were established. Using different degradation methods and separation techniques the 18S+26S RNA of 8-day-old wheat seedlings grown in the light was found to contain 5-methylcytidine, 3-methylcytidine, 5-methyluridine, 3-methyluridine, 5-carboxymethyluridine, 1-methyladenine, N-methyladenine, 5-hydroxymethylcytidine, O²-methyluridine, O²-methylcytidine, pseudouridine, O²-methylpseudouridine, N²,N²-dimethylguanine, 1-methylguanine, ribothymidine and some unknown minor constituents. On the other hand, there were only a few minor nucleotides in the rRNA of etiolated wheat seedlings. Cycloheximide, a cytoplasmic protein synthesis inhibitor, simulated etiolation in that it reduced the number of minor nucleotides in rRNA, whereas chloramphenicol, a chloroplast protein synthesis inhibitor, had no significant effect on the minor nucleotide content of rRNA. This finding suggests that illumination may cause de novo synthesis of cytoplasmic modifying enzymes leading to the formation of highly modified rRNAs.Abbreviations m⁶A N⁶-methyladenine - m¹A 1-methyladenine - 5hmc 5-hydroxymethylcytidine - Cm O²-methylcytidine - m⁵C 5-methylcytidine - m³C 3-methylcytidine - m¹G 1-methylguanine - m ₂ ² G N², N²-dimethylguanine - pseudouridine - m O²-methylpseudouridine - Um O²-methyluridine - m³U 3-methyluridine - m⁵U 5-methyluridine - cm⁵U 5-carboxymethyluridine - rT ribothymidine - Pur purine - Pyr pyrimidine - RNase ribonuclease - UV ultra violet - p phosphate     

The “biological ego”. From Garrod's “chemical individuality” to Burnet's “self”

Starting from the conceptual premises of Garrod, who as long ago as 1902 spoke of chemical individuality, and of Burnet (1949), who recognized as self one's own molecular antigenic structures (as opposed to the antigenic alien: the non- self), the discovery and understanding of HLA antigens and of their extraordinarily individual and differentiated polymorphisms have gained universal recognition. Transplant medicine has now dramatically stressed, within man's knowledge of himself, the characteristic of his biological uniqueness. Today man, having become aware of being a biological antigenic-molecular individuality which is unique and different from that of all of his fellow men (except for monozygotic twins), can therefore easily consider himself a true biological Ego.Abbreviations BMT bone marrow transplantation - GVHD graft versus host disease - HLA human leukocyte antigens - MHC major histocompatibility complex - MLC mixed lymphocyte culture - MLR mixed lymphocyte reaction     

Ultrastruktur und Bildung von Poren im Endothel von porösen und geschlossenen Kapillaren

Zusammenfassung An einer Reihe von normalen und pathologisch veränderten Organen wird die Porenstruktur, Porenbildung und Porenrückbildung elektronenmikroskopisch untersucht. Die Endothelpore ist eine Diskontinuität in der Endothelwand mit einem sehr konstanten Durchmesser von 500 Å. Das Diaphragma ist nur mit der äußeren Membranlamelle am Porenrand verbunden. Diaphragmalose Poren sind etwas größer (Ø650 Å), zeigen einen glatten Porenrand und kommen besonders in verdichteten Endothelteilen vor. Frustrane Poren münden blind in Vakuolen oder liegen in porösen Endothelfalten im Gefäßlumen. Die eigentliche Bildung der Poren geschieht immer in abgeflachten ( 800 Å) Endothelteilen. Die vorbereitende Abflachung geht jedoch in den verschiedenen Endothelzonen (Periksryon, dicker Endothelwand, Cytoplasmainseln) unterschiedliche Wege. Alle diese Vorgänge stellen Vesikulation in besonderer Lage und mit besonderer Fusionsrichtung der Vesikel dar. Wegen dieser Unterschiede wird die Endothelwand in 4 Zonen eingeteilt: Perikaryon; dicke, porenlose Wandteile mit cytoplasmatischen Vesikeln; dünne, porenhaltige Teile ohne Zellorganellen; dicke Cytoplasmainseln, die die porösen Wandteile voneinander trennen. Der Vorgang der Porenrückbildung bleibt unklar. Vielleicht besteht er in der Faltung des Endothels, die zu porösen Vakuolen führt. Die Porenbildung verändert die Endotheloberfläche nicht, kann aber das Cytoplasmavolumen vermindern. Der Aufbau des Diaphragmas sowie der Mechanismus und die auslösenden Faktoren der Porenbildung werden diskutiert.

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Summary Ultrastructure, formation and disappearance of endothelial pores was studied electron microscopically in several normal or experimentally changed organs. Pores being discontinuies in the endothelial wall have a very constant diameter of 500 Å. The diaphragm at the margin of the pore is in contact with only the outer lamella of the unit membrane. Pores without a diaphragm being somewhat larger (Ø 650 Å) show a smoother margin and are to be found in endothelia with dense cytoplasm. Frustrated pores form blind openings in vacuoles or are situated in porous endothelial folds within the vessel lumen. Pores alway are formed in flattened parts of endothelium ( 800 Å). In thick capillary walls the endothelium previously is flattened by vesiculation, which differs in different zones of the wall (Perikaryon, thick continuous endothelium, and cytoplasmic islands in porous capillaries) in location and direction of vesicle fusion. Because of these differences the endothelial wall is divided in 4 zones: Perikaryon; thick parts without pores containing cytoplasmic vesicles etc.; flattened, porous parts containing no cytoplasmic organelles; thick cytoplasmic islands which separate porous parts. The process removing pores is not clear. Perhaps they are removed by folding of the endothelial surface and formation porous vacuoles. Formation of pores dosn't enlarge or reduce the surface, but may reduce the cytoplasmic volume of endothelium. The nature of diaphragm as well as the mechanism and releasing factors of the formation of pores are discussed.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft     

Carboxyl-terminal modification alters the subunit interactions and assembly pathways of normal and sickle hemoglobins

Parallel isofocusing studies established that carboxypeptidase A removal of the His-146 (HC3) and Tyr-145 (HC2) residues of heme subunits affected the assembly properties of both Des (A) and Des (S) with heme chains, albeit to differing degrees. Indeed, the rate of Des (A) oligomer dissociation (k ₁), as determined by visible spectroscopy, was 4.3-fold faster than that of its native (A) counterpart. Furthermore, Soret spectral studies have affirmed distinct rates of normal (HbA), sickle (HbS), and Des HbA hemoglobin assembly (k₂) from their and [Des (A)] heme-containing monomers. Matching kinetic analysis of Des (A) and Des (S) chain assembly (with an identical chain) revealed 4.6- and 7.8-fold faster combination rates than those seen for (A) and (S) chains, respectively. This 3-fold disparity in rates strongly supports the critical role of the -6 (A3) residue, and its amino-terminal region, in chain partner recognition and subsequent human hemoglobin assembly.     

Purification and characterization of aspartate aminotransferase from developing embryos of the camel tick Hyalomma dromedarii

Aspartate transaminase (AST) activity in the camel tick Hyalomma dromedarii was followed throughout embryogenesis. During purification of AST to homogeneity, ion exchange chromatography lead to four separate forms (termed I, II, III and IV). AST II with the highest specific activity was pure after chromatography on Sephacryl S-300. The molecular mass of AST II was 52KDa for the native enzyme, composed of one subunit of 50KDa. AST II had a Km value of 0.67mM for -ketoglutarate and 15.1mM for aspartate. AST II had a pH optimum of 7.5 with heat stability up to 50°C for 15min. The enzyme was activated by MnCl₂, and inhibited by CaCl₂, MgCl₂, NiCl₂, and ZnCl₂.     

Expression of a chimeric stilbene synthase gene in transgenic wheat lines

A chimeric stilbene synthase (sts)gene was transferred into wheat. Stilbene synthases play a role in the defence against fungal diseases in some plant species (e.g. groundnut or grapevine) by producing stilbenetype phytoalexins like resveratrol. Resveratrol is also claimed to have positive effects to human health. Embryogenic scutellar calli derived from immature embryos of the two commercial German spring wheat cultivars Combi and Hanno were used as target tissue for cotransformation by microprojectile delivery. The selectable marker/reporter gene constructs contained the bargene either driven by the ubiquitinpromoter from maize (pAHC 25, also containing the uidAgene driven by the ubiquitinpromoter), or by the actinpromoter (pDM 302) from rice. The cotransferred plasmid pStil 2 consisted of a grapevine stscoding region driven by the ubiquitin promoter. Eight transgenic Combi and one Hanno T_Oplant were obtained and, except one Combi T_Oplant, found to be cotransformants due to the integration of both the stsgene and the selectable marker or reporter genes. Expression of the stsgene was proven by RTPCR, and, for the first time, by detection of the stilbene synthase product resveratrol by HPLC and mass spectrometry. The stsgene was expressed in four of the seven transgenic Combi T_{_o}plants. Two of the respective T₁progenies segregated in a Mendelian manner were still expressing the gene. Investigations into methylation of the stsgene showed that in three nonexpressing progenies inactivation was paralleled by methylation.     

Studies on aneuploids of Petunia

Summary The seven possible primary trisomics of Petunia (2 n= 14) located in the progenies of triploid, hypertriploid and hypotriploid plants were distinguished from one another and from diploid on the basis of cytological and morphological criteria. They were provisionally named as Oval, Semi, Slender, Pseudonormal, Arrow, Narrow and Giant. In three of the trisomics, the extra chromosome was identified for the first time at pachytene stage. Postpachytene studies revealed no precise relationship between the length of extra chromosome and the frequency of multiple association.     

Restriction fragment analysis of the secalin loci of rye

Analyses of wheat/rye addition lines by Southern blotting confirmed the presence of sequences related to theSec 1, Sec 2, andSec 3 loci on chromosomes 1R and 2R. Comparison of the 1R and 2R addition lines allowed the identification of -secalin genes atSec 1 andSec 2, respectively, while -secalin and -secalin genes atSec 1 were discriminated by comparative hybridization with three probes: -secalin, total -secalin, and 3 -secalin. The high molecular weight (HMW) secalin genes atSec 3 were identified using a homologous HMW subunit probe from wheat. Gene copy numbers were estimated as about 40–60 for -secalins, 5–10 for -secalins, and 2 for HMW secalins. Comparison of individual plants of cv. Gazelle showed a high degree of polymorphism, particularly for sequences related to -secalins and HMW secalins.     

Synthetic substrate analogues for UDP-GlcNAc: Manα1-6R β(1-2)-N-acetylglucosaminyltransferase II. Substrate specificity and inhibitors for the enzyme

UDP-GlcNAc: Man1-6R (1-2)-N-acetylglucosaminyltransferase II (GlcNAc-T II; EC 2.4.1.143) is a key enzyme in the synthesis of complexN-glycans. We have tested a series of synthetic analogues of the substrate Man1-6(GlcNAc1-2Man1-3)Man-O-octyl as substrates and inhibitors for rat liver GlcNAc-T II. The enzyme attachesN-acetylglucosamine in 1-2 linkage to the 2-OH of the Man1-6 residue. The 2-deoxy analogue is a competitive inhibitor (K _i=0.13mm). The 2-O-methyl compound does not bind to the enzyme presumably due to steric hindrance. The 3-, 4- and 6-OH groups are not essential for binding or catalysis since the 3-, 4- and 6-deoxy and -O-methyl derivatives are all good substrates. Increasing the size of the substituent at the 3-position to pentyl and substituted pentyl groups causes competitive inhibition (K _i=1.0–2.5mm). We have taken advantage of this effect to synthesize two potentially irreversible GlcNAc-T II inhibitors containing a photolabile 3-O-(4,4-azo)pentyl group and a 3-O-(5-iodoacetamido)pentyl group respectively. The data indicate that none of the hydroxyls of the Man1-6 residue are essential for binding although the 2- and 3-OH face the catalytic site of the enzyme. The 4-OH group of the Man-O-octyl residue is not essential for binding or catalysis since the 4-deoxy derivative is a good substrate; the 4-O-methyl derivative does not bind. This contrasts with GlcNAc-T I which cannot bind to the 4-deoxy-Man- substrate analogue. The data are compatible with our previous observations that a bisectingN-acetylglucosamine at the 4-OH position prevents both GlcNAc-T I and GlcNAc-T II catalysis. However, in the case of GlcNAc-T II, the bisectingN-acetylglucosamine prevents binding due to steric hindrance rather than to removal of an essential OH group. The 3-OH of the Man1-3 is an essential group for GlcNAc-T II since the 3-deoxy derivative does not bind to the enzyme. The trisaccharide GlcNAc1-2Man1-3Man-O-octyl is a good inhibitor (K _i=0.9mm). The above data together with previous studies indicate that binding of the GlcNAc1-2Man1-3Man- arm of the branched substrate to the enzyme is essential for catalysis. Abbreviations: GlcNAc-T I, UDP-GlcNAc:Man1-3R (1-2)-N-acetylglucosaminyltransferase I (EC 2.4.1.101); GlcNAc-T II, UDP-GlcNAc:Man1-6R (1-2)-N-acetylglucosaminyltransferase II (EC 2.4.1.143); MES, 2-(N-morpholino)ethane sulfonic acid monohydrate.     

Axillary shoot induction and plant regeneration in Plantago ovata Forssk

Axillary shoot induction and plant regeneration were obtained in Plantago ovata. The optimum medium for inducing axillary shoots was Murashige & Skoog (MS) medium [5] supplemented with 4.6 M kinetin and 0.05 M NAA. Rooting of shoots was best on half-strength MS medium containing 5.0 M IBA and 0.05 M kinetin. The regenerated plants were similar to the control plants in karyotypic and phenotypic details.     

Growth,photosynthesis and transpiration in Psophocarpus tetragonolobus (L.) DC cultivar ‘UPS 99’

Two methods (whole-plant growth analysis and gas exchange) were used to measure the response of Psophocarpus tetragonolobus (L.) DC cultivar UPS 99 to the environment. This plant had an optimal temperature for root growth of 25°C, its rate of acetylene reduction (when inoculated with Rhizobium, strain RRIM 56) was maximal at 30°C and it required an atmospheric temperature of about 35°C for optimal shoot growth. Maximum water-use efficiency was ca. 33 mg CO₂·g H₂O^-1. The rate of photosynthesis reached a plateau at 900 vpm CO₂-this condition also gave the lowest rate of transpiration. Under normal conditions, the light compensation point was at 1.7 klx, while that for CO₂ was 60 vpm. Photorespiration diminished gross photosynthesis of P. tetragonolobus by forty percent. Water stress (as measured by sensitivity to slightly increased CO₂ levels) caused rapid closure of stomata, and the response was remembered for up to five days.

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Zusammenfassung Mit Hilfe von zwei Methoden (Wachstumsanalysen ganzer Pflanzen und Gaswechselmessungen) wurde die Reaktion von Psophocarpus tetragonolobus (L.) DC der Sorte UPS 99 auf Umwelteinflüsse ermittelt. 25°C war die optimale Temperatur für das Wurzelwachstum. Die Acetylenreduktionsrate (die Pflanzen waren geimpft worden mit Rhizobium RRIM 56) war am höchsten bei 30°C. 35°C waren notwendig für maximales Sproßwachstum. Der günstigste Wasserausnutzungskoeffizient lag bei ungefähr 33 (mg CO₂·g H₂O^-1). Die Photosyntheseraten wurden durch Erhöhung der CO₂-Konzentration gesteigert. Bei Konzentrationen über 900 vpm CO₂ konnte allerdings keine weitere Steigerung mehr festgestellt werden. Bei 900 vpm CO₂ waren die Transpirationsraten am niedrigsten. Unter normalen Bedingungen stellte sich der Lichtkompensationspunkt bei 1,7 klx ein. Der CO₂-Kompensationspunkt lag bei 60 vpm CO₂. Die Photorespiration verminderte die Photosynthese von P. tetragonolobus um 40%. Wasserstreß vergrößerte die Empfindlichkeit der Stomata gegenüber etwas erhöhten CO₂-Konzentrationen (die Stomata schließen). Diese Empfindlichkeit war bis zu 5 Tagen nach der Streßbehandlung noch meßbar.

     

Comparative residual toxicities of pesticides to the predator Agistemus industani (Acari: Stigmaeidae) on citrus in Florida

Residual toxicities of registered and selected experimental pesticides used on citrus against Agistemus industani Gonzalez (Acari: Stigmaeidae) were compared. Pesticides considered highly toxic to A. industani were: abamectin 0.15 EC at 731ml/ha+FC 435-66 petroleum oil at 46.8l/ha, pyridaben 75WP at 469g/ha, ethion 4EC at 7.01l/ha+FC 435-66 petroleum oil at 46.8l/ha, propargite 6.55 EC at 3.51l/ha, chlorfenapyr 2SC at 1.46l/ha applied alone or in combination with FC 435-66 petroleum oil at 46.8l/ha, sulphur 80DF at 16.81kg/ha, dicofol 4EC at 7.01l/ha, fenbutatin oxide 50WP at 2.24kg/ha, benomyl 50WP at 2.24kg/ha, benomyl 50WP at 1.68kg/ha+ferbam 76 GF at 5.60kg/ha, ferbam 76GF at 11.21kg/ha, neem oil 90EC at 46.8l/ha, and copper hydroxide DF (40% metallic copper) at 4.48kg metallic copper/ha+FC 435-66 petroleum oil at 46.8l/ha. Pesticides that were moderately to slightly toxic included: copper sulphate 98% at 4.48kg metallic copper/ha+FC 435-66 petroleum oil at 46.8l/ha, fenbuconazole 2F at 280ml/ha+FC 435-66 petroleum oil at 46.8l/ha, FC 435-66 petroleum oil applied alone at 46.8l/ha or 23.4l/ha, and diflubenzuron 25WP at 1.40kg/ha. Pesticides that were non-toxic included: fenbuconazole 2F at 585ml/ha, malathion 57EC at 5.85l/ha, FC 435-66 petroleum oil at 46.8l/ha, carbaryl 80S at 3.36kg/ha, chlorpyrifos 4EC at 4.68l/ha, and formetanate 92SP at 1.12kg/ha. Understanding the toxic effects of field weathered pesticides against key predacious mite species is important for effective IPM. The results of this study provide a comparison of direct and indirect toxic effects of various pesticides to A. industani under field conditions.     

DNA variants within the 5′-flanking region of milk-protein-encoding genes II. The β-lactoglobulin-encoding gene

For the detection of polymorphisms within the 5-flanking region of the -lactoglobulin (-LG) -encoding gene a nucleotide sequence containing 795 bp of the promoter and 59 bp of exon I was cloned and sequenced. After comparing the sequence from the DNA of 11 diverse cows (different breeds and milk-protein yields), 14 singlebp substitutions were identified within the 5-flanking region and two in the 5-untranslated region (5-UTR) of exon I. Some of the variants are located in potential binding sites for trans-acting factors or in the 5-UTR. A PCR-based RFLP analysis was performed, and the genotypes of an additional 60 cows were identified at five variable 5-flanking sites. The results reveal three frequent combinations between the A and B alleles of the protein-coding region and the novel 5-flanking DNA variants. This finding may explain the differences of the protein-variant-dependent -LG synthesis (A>B) observed in vivo. A sequence comparison of the bovine and ovine promoters reveals an homology of 92.8% and shows a higher degree of conservation between positions -600 and -300.     

Transformation of Atriplex gmelini plants from callus lines using Agrobacterium tumefaciens

Atriplex gmelini plants were regenerated via organogensis from hypocotyl explants. Callus lines were induced from the hypocotyl explants on Linsmaier and Skoog (LS) medium supplemented with 1 M benzyladenine and 5 M -naphthaleneacetic acid in the dark. Shoots were regenerated from the callus lines on LS medium supplemented with 20 M thidiazuron and 0.1 M -naphthaleneacetic acid under a high-intensity light condition (450 mol m^–2 s^–1). The regenerated shoots were rooted on LS medium without growth regulators to obtain fully developed plants. We succeeded in transforming Atriplex gmelini from callus lines using Agrobacterium tumefaciens.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Action of rat liver Galβ1-4GlcNAc α(2-6)-sialyltransferase on Manβ1-4GlcNAcβ-OMe,GalNAcβ1-4GlcNAcβ-OMe,Glcβ1-4GlcNAcβ-OMe and GlcNAcβ1-4GlcNAcβ-OMe as synthetic substrates

Incubation of synthetic Man\1-4GlcNAc-OMe, GalNAc1-4GlcNAc-OMe, Glc1-4GlcNAc-OMe, and GlcNAc1-4GlcNac-OMe with CMP-Neu5Ac and rat liver Gal1-4GlcNAc (2-6)-sialyltransferase resulted in the formation of Neu5Ac2-6Man1-4GlcNAc-OMe, Neu5Ac2-6GalNAc1-4GlcNAc-OMe, Neu5Ac2-6Glc1-4GlcNAc-OMe and Neu5Ac2-6GlcNAc1-4GlcNAc-OMe, respectively. Under conditions which led to quantitative conversion of Gal1-4GlcNAc-OEt into Neu5Ac2-6Gal1-4GlcNAc-OEt, the aforementioned products were obtained in yields of 4%, 48%, 16% and 8%, respectively. HPLC on Partisil 10 SAX was used to isolate the various sialyltrisaccharides, and identification was carried out using 1- and 2-dimensional 500-MHz¹H-NMR spectroscopy.Abbreviations 2D 2-dimensional - CMP cytidine 5-monophosphate - CMP-Neu5Ac cytidine 5-monophospho--N-acetylneuraminic acid - COSY correlation spectroscopy - DQF double quantum filtered - HOHAHA homonuclear Hartmann-Hahn - MLEV composite pulse devised by M. Levitt - Neu5Ac N-acetylneuraminic acid - Neu5Ac2en 2-deoxy-2,3-didehydro-N-acetylneuraminic acid     

Synthesis of hexaploid (AABBCC) somatic hybrids: a bridging material for transfer of ‘tour’ cytoplasmic male sterility to different Brassica species

Most of the alloplasmic cytoplasmic male sterility (CMS) systems are known to be associated with a number of floral abnormalities that result from nuclear-cytoplasmic incompatibilities. One such system, tour, which is derived from Brassica tournefortii, induces additional floral abnormalities and causes chlorosis in Brassica spp. While the restorer for this CMS has been reported to be present in B. napus, in B. juncea, where the abnormalities are more pronounced, no restorer has yet been identified. Rectification of these floral abnormalities through mitochondrial recombinations and chloroplast replacement might result in the improvement of this CMS system. As organelle recombinations can possibly be achieved only by somatic cell hybridization, fusion experiments were carried out between hygromycin-resistant B. juncea AABB carrying tour cytoplasm and phosphinotricin-resistant, normal B. oleracea CC to generate AABBCC hexaploid somatic hybrids. The presence of selectable marker genes facilitated the selection of hybrids in large numbers. The resulting hybrids showed wide variation in floral morphology and organelle composition. Regenerants with normal, male-sterile flowers having recombinant tour-or oleracea-type mitochondria and oleracea-type chloroplasts were obtained. Hybrids with male-fertile flowers were also obtained that had recombined tour mitochondria. The AABBCC hexaploid hybrids synthesized in the present study were successfully utilized as a bridging material for transferring variability in the organelle genome simultaneously to all the digenomic Brassica species, and all of these hybrids are now being stabilized through repeated backcrosses to the allopolyploid crop brassicas.