The effect of some macronutrients on adventitious root development on scion apple cultivars in vitro

The influence of some macronutrients, especially NH₄NO₃ and KNO₃, on root development of microcuttings from 3 apple scion cultivars is discussed. A reduction of the level of NH₄NO₃ in the medium from full strength to 1/4 strength significantly increased the percentage rooting of Gala and Royal Gala, but not Jonagold. Further reduction of NH₄NO₃ level from 1/4 strength to zero significantly reduced the percentage of rooting in Gala but not Royal Gala. Jonagold rooted best at zero concentration NH₄NO₃. Without NH₄NO₃, rooting percentages were as high as 100% for all 3 cultivars when KNO₃ was provided at full strength. The results show that adventitious roots can be induced on apple scion cultivars by media manipulation.     

Monosomic analysis of heading date and spikelet number in the common wheat (Triticum aestivum L.) multispikelet line ‘Noa’

Summary Genetic analysis of heading date and spikelet number was carried out in the common wheat (Triticum aestivum L.) multispikelet line Noa, by using the monosomic series of the regular line Mara. Noa's high number of spikelets was found to be controlled by a recessive major gene on chromosome 2D; a slight reduction in spikelet number was induced by another recessive gene on Noa's 7A chromosome. Noa's late heading date was found to be controlled by two recessive genes, located on chromosome 2D (a major effect) and 6B (a minor effect). The nature of the genes located on Noa's 2D chromosome and the relationship between spikelet number and heading date are discussed.     

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     

Hexahydroindanone derivatives of steroids formed by Rhodococcus equi

Summary A mutant strain of Rhodococcus equi accumulates three metabolites from the androst-4-ene-3,17-dione or from its degradation intermediate, 3a-H-4(3'-propionic acid)-7a-methylhexahydro-1,5-indanedione (MEPHIP). These three metabolites are: 3a-H-4a(3'-propionic acid)-5-hydroxy-7a-methylhexahydro-1-indanone--lactone (HIL); 3a-H-4(3'-trans acrylic acid)-5-hydroxy-7a-methylhexahydro-1-indanone (^2'-5-hydroxy-MEPHIP); and 3a-H-4(3'-hydroxy-3'-propionic acid)-5-hydroxy-7a-methylhexahydro-1-indanone (3'-hydroxy-HIL). The behaviour of this mutant allows us to propose a pathway for degradation of the intermediates, methylperhydroindanone propionates. However, during this degradation, the side-chain propionate was eliminated by a-oxidation mechanism. Offprint requests to: A. Miclo     

2′(3′),5′-ADP inhibits initiation-dependent protein synthesis in a cell-free system from Ehrlich ascites tumor cells

When tested in a poly(U)-dependent polyphenylalanine synthesizing system and in a postnuclear supernatant, both derived from Ehrlich ascites tumor cells, 2(3),5-ADP did not affect chain elongation of polypeptide synthesis. In a cell-free system which was dependent on initiation and programmed by natural mRNA, however, the amino acid incorporating activity was suppressed to about 10% of the control in the presence of 1 mM 2(3),5-ADP. The inhibitor was shown not to interfere with the attachment of poly(U) to the small ribosomal subunit and with the formation of mRNA-80S ribosome complexes in a complete protein synthesizing system. The subsequent attachment of a 40S ribosomal subunit to the mRNA-80S ribosome complex and the formation of polysomes, however, was depressed by the inhibitor. The experimental results suggest that 2(3),5-ADP inhibits initiation-dependent protein synthesis between monosome formation and the formation of the first peptide bond(s).     

Kinetics of the reconstitution of hemoglobin from semihemoglobins α and β with heme

Kinetics of the reconstitution of hemoglobin from semihemoglobins and with hemin dicyanide have been investigated using three kinds of stopped-flow technique (Soret absorption, fluorescence quenching of tryptophan, and Soret CD). The semihemoglobins and are occupied by heme in the and chains, respectively, the other chain being heme-free. Based on the kinetic results, the following scheme for the reconstitution is proposed; First, hemin dicyanide enters the pocket-like site of the apo chains. Second, in semihemoglobin , the CN-ligand in the fifth coordination position of iron is replaced by the imidazole ring of the proximal His immediately after the heme insertion. In contrast, semihemoglobin changes its conformation after the heme insertion, and this is followed by the ligand replacement. Finally, the partial structure changes induced by the ligand replacement propagate onto the whole molecule and the final conformation is attained. The results indicate that semihemoglobin retains a more rigid and organized structure, and more closely approaches its final structure than does semihemoglobin . Correspondence to: Y. Kawamura-Konishi     

Objective characterization of cells in terms of microscopical parameters: An example from muscle histochemistry

Summary A quantitative histochemical analysis of almost 200 mouse triceps surae muscle fibres is presented, together with some data from similar surveys of rabbit skeletal muscles. In the main work, ten parameters are considered: mean diameter, and reaction intensities (estimated as apparent absorbances) of three markers for oxidative-lipolytic metabolism, three for metabolism associated with glycolysis and three for the type of myosin. Cytoarchitecture of one deposit (succinate dehydrogenase) is also noted.Frequency histograms for each parameter and correlation analyses for all possible pairings demonstrate that markers within the same metabolic system are not truly equivalent. Therefore, fibre typing in terms of just one marker from each system cannot be independent of the markers used. Selecting the most sharply discriminatory pair-myosin ATPase (following formalin and alkaline pretreatment) and glycogen phosphorylasea — one isolates four more-or-less discrete clusters of points. Taking succinate dehydrogenase also into account, to indicate characteristic oxidative levels within clusters, one can label the indicated fibre types (following a well-established muscle terminology) as fast, essentially glycolytic (FG), fast, oxidative and glycolytic (FOG), fast, essentially-oxidative (FO) and slow, essentially oxidative (SO). However, with either -glycerophosphate dehydrogenase or the periodic acid-Schiff reaction (PAS) as glycolytic marker, the FO-group is not separated from the FOG; and with oxidative level as a primary clustering criterion FG and FOG groups are continuous. An entirely different basis for classification-cytoarchitecture-also suggests four fibre types but the divisions most comparable to the FG/FOG and FOG/FO boundaries are best located somewhat differently again.Some of the techniques of formal cluster analysis are next introduced. These are ways of searching for similarities (defined in terms of various objective criteria) in large volumes of essentially multivariate data.Within a sample, considered representative of acceptably artefact-free fibres, virtually the same four groups as before are identified. The only difference is that what were earlier grouped as the most oxidative FG fibres are now classed FOG; the acid-pretreated myosin ATPase reaction (previously little considered) contributes to this reclassification. At the five cluster level, a strong tendency exists for this small group, designated FG(O), to appear separately. At the two-cluster level classical distinctions in terms of high/low oxidative capacity, glycolytic capacity and myosin ATPase activity are each favoured by different similarity criteria.Surveying the whole sample of fibres, only criteria which favour non-rambling clusters produce similar results to those above. However, an artefact in one reaction, for which there is strong internal evidence, is able to explain almost all other effects. These results do not prove the biological rightness of a 4–5 cluster pattern, but they do demonstrate its mathematical strength and the reactions upon which it depends.The suggestion is made that cluster analysis and related multivariate statistical methods could profitably be applied to a wide range of further problems in cell taxonomy.     

Towards a pluralistic concept of function function statements in biology

The meaning of function statements is not clear. Several authors have come up with different explications. By interviewing biologists I tried to get a picture of how they think about function. Two explications of Feature X of organism S has function F came to the fore: (1) X contributes to F and F contributes to survival/reproduction of S and (2) X does F and that contributes to the evolutionary development of X in S via natural selection. Most biologists also related function to adaptation. Gould and Vrba criticize the ordinary use of adaptation in biology. They propose to use it only in the sense of features developed by natural selection for their current role and to use exaptation for features enhancing fitness, but not developed for this by natural selection. This, however, leaves a terminological gap, because as a consequence only effects of adaptations are functions. Effects of exaptations and effects which are not beneficial, like the production of heart sounds, are placed on the same level. That is not in accordance with the practice of biology. That is why a distinction is made between general, adaptive and exaptive functions: function as a pluralistic concept.Revised version of an earlier paper, published in Dutch in Kennis en Methode, November 1988.     

Two novel isoneolacto-undecaglycosylceramides carrying Galα1→3Lewisx on the 6-linked antenna and N-acetylneuraminic acidα2→3 or Galactose α1→3 on the 3-linked antenna, expressed in porcine kidney

Three sialosylated and three neutral glycosphingolipids sharing a common iso-neolacto core were isolated from porcine kidney cortex. They were purified by preparative HPTLC, and were characterized by partial exoglycosidase hydrolysis followed by thin layer chromatography and immunostaining with anti-Gal13Gal, anti-type 2 lactosamine and anti-Lewisx antibodies, methylation analysis, MALDI-TOF mass spectrometry and 1H-NMR spectroscopy. Among neutral glycolipids, one was a known structure, VI3VI3(Gal)2-iso-nLc8Cer, and two were novel structures differing by the number of Gal3Lewisx determinants: VI3VI3(Gal)2V3Fuc-iso-nLc8, and VI3VI3(Gal)2 V3V3(Fuc)2-iso-nLc8. The single Gal3Lewis x determinant was found on the 6-linked antenna. Among sialosylated glycolipids, two had been previously found in other species and tissues, VI3VI3(NeuAc)2-iso-nLc8, and VI3NeuAcVI3Gal-iso-nLc8. A novel structure was discovered presenting a Gal3Lewisx determinant on the 6-linked antenna and a N-acetylneuraminic acid on the 3-linked antenna, VI3NeuAcVI3GalV3Fuc-iso-nLc8. These results indicate that, in vivo, the porcine kidney 3fucosyltransferase synthesizes the Gal3Lewisx determinant, acting on the 6-linked before the 3-linked Gal3neolactosamine, and appears unable to synthesize the sialosylated Lewisx determinant on neolactoseries glycolipids.     

Cytochemical localization of nicotinamide adenine dinucleotide phosphatase (NADPase) in bovine Leydig cells

Summary The ultrastructural localization of nicotinamide adenine dinucleotide phosphatase (NADPase) in bovine Leydig cells has been studied and compared with the pattern of thiamine pyrophosphatase (TPPase) and acid phosphatase distribution in these cells. Using -nicotinamide adenine dinucleotide phosphate (-NADP⁺) as substrate, a marked staining is observed in the intermediate Golgi saccules with some focal extension to the trans aspect. Cisternae on the cis side and associated vesicles yielded only slightly positive reactions. The pattern of NADPase localization is clearly different from that of TPPase which consistently stains only the trans Golgi elements. The specifity of NADPase for its substrate, -NADP⁺, was clearly demonstrated by using substrates modified in either the nicotinamide region e.g. -nicotinamide adenine dinucleotide phosphate (-NADP⁺), -thionicotinamide adenine dinuclcotide phosphate (Thio-NADP⁺), in the attachment site of the monoester phosphate group to the molecule (e.g. 2 monophospho-adenosine 5-diphosphoribose (ATP-ribose) or adenosine-5-monophosphate (5AMP). With these substrates only weak or negative reactions were obtained in the Golgi apparatus of the bovine Leydig cell.     

Glycoconjugates of the Rat Ciliary Body Epithelium: A Lectin Histochemical and Protein Blotting Study

The present study sought to identify and partially characterize the glycoconjugates specific to the double-layered ciliary body epithelium of the rat eye by lectin histochemistry and lectin blottings. Hydrated paraffin sections of Carnoy-fixed Sprague-Dawley rat eyes were stained with a panel of 21 different biotinylated lectins, followed by streptavidin-peroxidase and the glucose oxidase-diaminobenzidine-nickel staining procedure. The results of lectin histochemistry revealed that the inner epithelial layer was rich in GlcNAc(1,4)GlcNAc, -Gal, Gal(1,3)GalNAc, GalNAc(1,3)GalNAc/Gal, GalNAc(1,6)Gal, Fuc(1,2)Gal(1,4)GlcNAc and Gal(1,4)GlcNAc(1,2)Man(1,6) sugar residues as shown by its positive reactivities with S-WGA, PWA, DSA, GS-I-B4, PNA, DBA, SBA, WFA, UEA-I, LTA and PHA-E. The reactivities of GS-I-B4, PNA, DBA and SBA were restricted to the inner layer at the tips of the ciliary processes. On the other hand, the outer epithelial layer was stained evenly by DSA and Jacalin, and partly by MAA, showing that this epithelial layer was rich in GlcNAc(1,4)GlcNAc, Gal(1,3)GalNAc and NeuAc(2,3)Gal disaccharides. These lectin binding patterns of the ciliary body epithelium suggest a topographical and functional difference in this double cell-layered epithelium. Their possible roles in the secretion of aqueous humour and production of ciliary zonule are discussed. Some identified lectin markers specific to these two cell layers may be useful for further experimental studies. Glycoproteins extracted from the dissected ciliary body were separated by SDS-PAGE electrophoresis and analyzed by protein blottings with 8 different lectins. The results showed that at least 10 major membrane-bound glycoproteins, with molecular weights ranging from 30 to 150kD, rich in -GlcNAc, -Gal, /-GalNAc and NeuAc(2,6)Gal residues, were present in the microsomal fraction.     

Adoptions expérimentales de larves entre des fourmis de genres différents (II):Myrmica laevinodis Nylander etAnergates atratulus Schenck

Résumé Nous avons fait élever des larves d'Anergates atratulus par des ouvrières deMyrmica laevinodis à 22°C. Pour y parvenir, il n'est pas utile de faire hivernerensemble les larves d'Anergates et les ouvrières deMyrmica. La présence de larves autochtones n'empêche pas lesMyrmica d'élever des larves d'Anergates. Dans toutes les expériences lesMyrmica ont été soumises au fridavant de recevoir des larves d'Anergates. Aucune reine deMyrmica n'a été utilisée dans ces expériences.Sur les 64 larves d'Anergates que nous avons utilisées, 38 se sont transformées en imagos. C'est au début de l'adoption et au moment des métamorphoses que périrent la plupart des 26Anergates perdus. Les femelles vécurent en général 2 ou 3 jours et cherchèrent très tôt à quitter le nid natal. Les mâles vécurent 2 à 3 semaines.

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Summary Larvae ofAnergates atratulus were experimentally reared by workers ofMyrmica laevinodis, at 22°C. An overwintering of both larvae ofAnergates and workers ofMyrmica is not necessary for the success of that experiment. The presence of larvae ofMyrmica does not keep theMyrmica from rearing larvae ofAnergates. The workers ofMyrmica have been cooled, in all the experiments, before receiving larvae ofAnergates. No queen ofMyrmica have been used in that experiments.38 of the 64 larvae ofAnergates used became imagos. Most of the 26 lostAnergates died at the beginning of the adoption and during the metamorphosis. The females lived generally 2 or 3 days and tried, very early, to leave their native nest. The males lived 2 or 3 weeks.

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Anergates atratulus Myrmica laevinodis, 22 . bmecme Anergates Myrmica. Myrmica Anergates. Myrmica Anergates. Myrmica . 64 Anergates , 38 . 26 Anergates 2 3 . 2 3 .

     

Effects of transforming growth factor β, tumor necrosis factor α and interferon γ on pancreatic islet β-cell responsiveness to transforming growth factor α

The insulin-producing pancreatic islet -cell, characterized by low proliferative potential, is normally not responsive to the polypeptide epidermal growth factor (EGF) or its homolog transforming growth factor (TGF-). Since EGF receptors in other tissues can be up-regulated by other growth factors and by cytokines, we have in this paper investigated whether such a -cell responsiveness to TGF-, or EGF, can be conferred by co-culture with interferon (IFN-), tumor necrosis factor (TNF-) or transforming growth factor (TGF-) in various combinations. To this end, fetal rat pancreatic islets enriched in -cells were isolated and cultured for 3 days with or without 200 pM or 20 nM TGF-. It was found that neither of these TGF- concentrations affected -cell mitogenesis, insulin content or insulin secretion. However, IFN- (1000 U/ml) evoked a modest stimulation of -cell replication, while suppressing insulin secretion and leaving the islet insulin content unaltered. TNF- (1000 U/ml), on the other hand, affected none of these parameters either alone or in any combination with TGF- or IFN-. However, when TNF- or IFN-, either alone or in combination, were combined with the cytokine interleukin-1, this resulted in islet disintegration, whereas the latter cytokine alone did not exert any gross necrotic changes evident by light microscopy. TGF- (500 pM) stimulated insulin secretion but did not influence islet insulin content or -cell mitogenesis either alone or in combination with TGF- (200 pM or 20 nM). In no instance could any mitogenic or secretory response to low or high concentrations of TGF- be conferred by IFN-, TNF- or TGF- whether used alone or in combinations. Hence, responsiveness to TGF- or EGF in the -cell obviously cannot be achieved by any of these peptides.Abbreviations EGF epidermal growth factor - IFN- interferon - TGF- transforming growth factor - TGF- transforming growth factor - TNF- tumor necrosis factor      

Selection of isoresponsive genotypes in toria (Brassica campestris L.) based on the pattern of response to environmental variations: a proposed method

Summary Thirty-one toria genotypes were compared with three well-established cultivars, Ludhiana Composite-2, K-1 and TCSU-2 (standard testers). The genotypes, which were almost identical to a standard tester in response to environmental variations and which also had other desirable characteristics, were considered to be acceptable for commercial cultivation. Using this criterion, TCSU-7, TH-5 and TH-4 were found to be acceptable for commercial cultivation. TH-4 and TCSU-7 were found superior to TH-5 if r² can be considered as a measure of the agronomical manipulations expected in environmental variations.     

The effect of different growing conditions on water relations parameters of leaf epidermal cells of Tradescantia virginiana L.

Summary Tradescantia virginiana L. plants were cultivated under contrasting conditions of temperature, humidity, light quality and intensity, and nutrient status in order to investigate the effect of growth conditions on the water relations parameters of the leaf epidermal cells. Turgor pressure (P), volumetric elastic modulus (), half-time of water potential equilibration (T _1/2), hydraulic conductivity (L _p ) were measured with the miniaturized pressure probe in single cells of the upper and lower epidermis of leaves. Turgor differed (range: 0.1 bar to 7.2 bar) between treatments with lowest values under warm and humid conditions and additional supply of fertilizer, and highest values under conditions of low air humidity and low nutrient supply. The volumetric elastic modulus changed by 2 orders of magnitude (range: 3.0 bar to 350 bar, 158 cells), but was only affected by the treatments, in as much as it was dependent on turgor. The turgor dependence of , measured on intact leaves of T. virginiana, was similar to that for cells of the isolated (peeled) lower epidermis, where as a function of turgor was linear over the whole range of turgors. This result has implications for the discussion of pressure/volume curves as measured by the pressure bomb where changes in bulk leaf are frequently discussed as adaptations to certain treatments. The measurements of the hydraulic conductivity indicate that this parameter varies between treatments (range of means: 2.4×10^-6 cm s^-1 bar^-1 to 13.4×10^-6 cm s^-1 bar^-1). There was a negative correlation for L _p in cells of intact leaves as a function of turgor which was altered by the growing conditions. However, a correlation with turgor could not be found for cells from isolated epidermis or cells from a uniform population of plants. The large variation in L _p from cell to cell observed in the present and in previous studies was accounted for in a study of 100 cells from a uniform population of plants by the propagation of measurement errors in calculating L _p . The results suggest that in T. virginiana cellular water relations are changed mainly by the turgor dependence of .     

High-level Expression of Maize <Emphasis Type="Italic">γ</Emphasis>-zein Protein in Transgenic Soybean (<Emphasis Type="Italic">Glycine max</Emphasis>)

Primers were developed for 118 microsatellites isolated from grape (Vitis vinifera) genomic libraries enriched for (AC)n repeats. Only one microsatellite sequence matched other grape SSR-sequences in the GeneBank database. Genotyping was carried out in the parental lines and four offspring of two pseudo-test-cross populations, Cabernet Sauvignon x Seyval and Chardonnay x Bianca, and a further six other grape genotypes (V. vinifera Sultanina, Merlot, Syrah, Müller-Thurgau, Vitis Regent and V. riparia Gloire de Montpellier). A total of 108 microsatellites showed easily scorable alleles and 100 of them segregated according to a configuration suitable for mapping in either cross. A further 8 SSRs, although unsuitable for mapping in those crosses, showed polymorphism in the other genotypes tested. This set of markers was used, along with 75 microsatellites of other repeat-types, to fingerprint 46 offspring of the cross Chardonnay x Bianca. For each full-sib, individual heterozygosity and distance in repeat units between pairs of alleles at each locus (mean d²) were calculated as a tool for predicting highly outbred recombinant individuals. Six microsatellites with segregation ratios significantly distorted towards the lack of homozygous sibs were identified and mapped to linkage groups LG 3 and LG 5. Estimation of heterozygosity at genome-wide level and genotyping at loci for which homozygous sibs are discriminated against are discussed for marker-assisted background selection in outcrossing grapevines.     

A partial genome assay for quantitative trait loci in wheat (Triticum aestivum) using different analytical techniques

F₁ plants between two intervarietal chromosome substitution lines of European spring wheat varieties, Sicco (Chinese Spring 5B) and Highbury (Chinese Spring 5B), were used to produce 114 doubled haploid lines, 45 by the Hordeum bulbosum technique and 69 by anther culture. These two sets of lines were characterized for variation at a range of morphological, isozyme and RFLP marker loci, and genetic maps were developed with emphasis on chromosomes 6B, 7A, 7B and 7D. A subset of lines, scored for production traits in field trials in 1986 and 1987, were analysed for quantitative trait loci (QTL). The performance of the lines for the quantitative traits studied showed no overall differences due to the method of production of the lines. QTL were located on the linkage map for ear emergence time, height, tiller weight, yield and 50-grain weight using four analytical methods. Many of these effects showed genotype x year interaction.     

Plant chaperonins: a role in microtubule-dependent wall formation?

Summary The cytosolic chaperonin containing t-complex peptide-1 (CCT) is involved in the correct folding of newly synthetized actin and tubulin molecules. To get insight into potential additional functions of plant CCT, the localization of the subunit CCT was followed throughout cell cycle, cell elongation, and cell differentiation in the tobacco cell culture VBI-O with relation to the microtubular cytoskeleton by double-immunofluorescence and confocal microscopy. The CCT subunit was found to colocalize with sites of microtubule nucleation such as nuclear envelope and preprophase band. In addition, CCT was associated with tubulin in sites of elevated wall synthesis such as phragmoplast or along secondary-wall thickenings. CCT and its substrate tubulin were found to be soluble during periods of cytoskeletal dynamics, whereas sedimentable, vesicle-bound forms of CCT and tubulin prevailed during cell differentiation. The sedimentability of CCT was increased by calcium, whereas it was detached from microsomes by ATP. CCT can bind to both polymerized microtubules and tubulin dimers. These data suggest an additional function of plant CCT in microtubule-driven transport of vesicles that contain cell-wall material.Abbreviations CCT cytosolic chaperonin containing t-complex polypeptide 1     

Monoclonal antibody specific for α2→8-linked oligo deaminated neuraminic acid (KDN) sequences in glycoproteins. Preparation and characterization of a monoclonal antibody and its application in immunohistochemistry

Two particular types of sialoglycoproteins have been detected in fish: polysialoglycoproteins containing 28-linked polysialic acid (8Neu5Gc2) _n present in unfertilized Salmonidae fish eggs, and glycoproteins bearing oligo/polymers of deaminated neuraminic acids (KDN) found in the vitelline envelope of the eggs and ovarian fluid. We report the preparation and characterization of a monoclonal antibody specifically recognizing oligo/polymers of KDN sequences in glycoproteins and its application in immunohistochemistry. Fusion of spleen cells from a BALB/c mouse immunized with a KDN-rich glycoprotein (KDN-gp) containing (8KDN2) _n 6(KDN23Gal13GlNAc13) GalNAc1 residues, with mouse myeloma cells yielded a hybrid cell line producing a monoclonal antibody that bound to KDN-gp, but not to KDN-gp depleted of KDN residues. The specificity of the monoclonal antibody, designated mAb.kdn8kdn, was determined by an enzyme-linked immunosorbent assay using KDN-gp samples that varied in KDN content. These antigens were prepared by the selective removal of KDN residues from the native KDN-gp. The mAb.kdn8kdn reacted most strongly with the intact KDN-gp and less strongly with KDN-gp samples containing decreased numbers of KDN residues. The mAb.kdn8kdn was shown specifically to recognize the 28-linked oligo/polyKDN sequences, (8KDN2) _n , and to be able to distinguish specifically (8KDN2) _n chains from (8Neu5Ac2) _n and (8Neu5Gc2) _n chains. The antibody was used successfully for the immunohistochemical detection of reactive KDN epitopes in sections of paraffin embedded rat pancreas. Several controls verified the specificity of the immunohistochemical staining, thus providing the first demonstration of (8KDN2) _n sequences in a mammalian tissue. The mAb.kdn8kdn can now be used to search further for glycoconjugates containing (8KDN2) _n chains and will facilitate studies on their biosynthesis, intracellular localization and function.     

Leaf thickness and carbon isotope composition in the Crassulaceae

Summary Measurements of leaf thickness and ¹³C value were obtained for twenty species and three intergeneric hybrids of the Crassulaceae. The data include plants growing in their native habitats and also in greenhouse cultivation. There is a strong relationship between leaf thickness and leaf ¹³C values. The plants with the thickest leaves of ca. 7 to 11 mm had ¹³C values ranging from -11.5 to -13.8. Plants with leaves that were thinner than 2.0 mm all had ¹³C values that were more negative than -23. Plants having intermediate leaf thickness possessed intermediate ¹³C values. The leaf tissue of four genotypes spanning the range of leaf thicknesses all exhibited a two-fold or greater nocturnal increase in titratable acidity. It appears that the differences in leaf thickness and ¹³C values among the tested species are genetically determined.