In vitro regeneration of evergreen azalea from leaves

Rhododendron simsii Hellmut Vogel was regenerated using different types of explants, auxins and cytokinins. After a callus induction phase, with 2,4-dichlorophenoxyacetic acid or -naphthaleneacetic acid, adventitious shoot regeneration was obtained on a medium supplemented with thidiazuron or zeatin. With thidiazuron shoots were small and a subsequent elongation step was required before rooting. An elongation step was not required when zeatin was used. The duration of the callus induction phase was negatively correlated with the regeneration capacity.Abbreviations 2,4-d 2,4-dichlorophenoxyacetic acid - NAA -naphthaleneacetic acid - 2iP 6-(--dimethylallylamino)purine - NOA ß-naphthoxyacetic acid - BA 6-benzyladenine - IBA 1-H-indole-3-butyric acid - IAA 1-H-indole-3-acetic acid - TDZ thidiazuron - WPM woody plant medium     

Production of a thermostable alkali-tolerant xylanase from Bacillus circulans AB 16 grown on wheat straw

Bacillus circulans AB 16 was able to produce 50 IU/ml of xylanase, with negligible cellulase activity when grown on untreated wheat straw. The pH optimum of the crude enzyme was 6–7 with a temperature optimum of 80 C. The enzyme showed high pH and thermal stability retaining 100% activity at 60 C, pH 8 and 9 after 2.5 h of incubation. The residual activity at 70 C after 2.5 h was 62% and 45% at pH 8 and 9, respectively. At 75 C only 22.2% activity remained at pH 8 after 1 h incubation. Since Kraft pulp is alkaline this enzyme could be used for prebleaching of pulp at temperatures up to 70 C without pH adjustment.     

Linkage of restriction fragment length polymorphisms and isozymes in Citrus

Summary Genetic linkage analysis was performed using two segregating populations of citrus. One population arose from an intergeneric backcross of Citrus grandis (L.) Osb. cv Thong Dee and Poncirus trifoliata (L.) Raf. cv Pomeroy, using the former as the recurrent (female) parent. The other population came from an interspecific backcross of C. reticulata Blanco cv Clementine and C. x paradisi Macf. cv Duncan, using the former as the recurrent (male) parent. A total of 11 isozyme and 58 restriction fragment length polymorphisms were found to segregate in a monogenic fashion in one or both populations. Linkage analysis revealed that 62 of the loci examined mapped to 11 linkage groups, while 7 loci segregated independently from all other markers. Gene order was highly conserved between the maps generated from the two divergent segregating populations. Possible applications of the use of such maps in tree fruit breeding are discussed.     

Injury to potato leaves exposed to subzero temperatures in the absence of freezing

Electrolyte leakage was measured in hardened and nonhardened leaves of three potato species, Solanum tuberosum L., S. acaule Bitt. and S. commersonii Dun., and one interspecific cross, Alaska Frostless (S. acaule x S. tuberosum) when exposed to various subzero temperatures. The leaves were undercooled (no ice present) from 0°C to -12.5°C for 45 min and to-4°C for up to 10 d. Regardless of the degree of undercooling no injury was observed in any of the potatoes, hardened or nonhardened, for up to 12 h. After 5 d, however, electrolyte leakage was observed in hardened S. tuberosum, S. acaule and S. commersonii, and in nonhardened Alaska Frostless. After 10 d exposure all potatoes, hardened and nonhardened, showed a significant amount of electrolyte leakage as compared to their controls kept at 0°C for 10 d.Scientific Journal Series Paper No. 13842 of the Minnesota Agricultural Experiment Station, St. Paul, Minn     

N-andO-alkylation of glycoconjugates and polysaccharides by solid base in dimethyl sulphoxide/alkyl lodide

O-Methylation of simple neutral oligosaccharides is readily accomplished in dimethyl sulphoxide containing solid sodium hydroxide and methyl iodide [Cincanu I, Kerek F (1984) Carbohydr Res 131209-17]. This procedure has been extended to 2-acetamido-2-deoxy sugars and sialic acid-containing oligosaccharides. CompleteO-andN-methylation was in most cases achieved in 15 min. Esterification of carboxylic groups in uronic acids was fast and resulted in concomitant -elimination. The method is also suitable for methylation of glycoproteins and glycosphingolipids. Polysaccharides can also be methylated by this technique. Analysis of the products by gas-liquid chromatography and mass spectrometry showed no degradation products.Abbreviations lacto-N-tetraose LcOse₄, Gal3GlcNAc3Gal4Glc - lacto-N-fucopentaose III III³Fuc-nLcOse₄, Gal4[Fuc3]GlcNAc3Gal4Glc - trihexosylceramide GbOse₃Cer, Gal4Gal4Glc1-1Cer - globoside GbOse₄Cer, GalNAc3Gal4Glc1-1Cer - FAB-MS fas atom bombardment mass spectrometry     

Steroid Polyols from the Far Eastern Starfish Henricia sanguinolenta and H. leviuscula leviuscula

Two new asterosaponins, (20R)-3-O--D-(2-O-methylxylopyranosyl)-24-propylcholest-4-ene-3,6,8,15,16,29-hexaol (sanguinoside A) and (20R,24S)-3-O--D-(2,3,4-tri-O-methylxylopyranosyl)-5-cholestane-3,4,6,8,15,24-hexaol (sanguinoside B), were isolated from two species of Pacific Far Eastern Starfish Henricia sanguinolenta and H. leviuscula leviuscula, collected in the Sea of Okhotsk. Both glycosides contain aglycones with pentahydroxysteroid nuclei of similar structures, which are substituted at the 3-hydroxy group with differently methylated -D-xylosyl residues. Sanguinoside A has an unusual structure of its aglycone side chain, whereas sanguinoside B has a unique permethylated carbohydrate chain. In addition, laevisculoside G, a known glycoside, was identified in the H. leviuscula starfish. The structures of the isolated glycosides were established by interpreting their spectral data and by comparing their spectral characteristics with those of known compounds.     

Localization of genes coding for biochemical traits on the second chromosome of Drosophila imeretensis Sokolov (D. littoralis Meigen)

We have investigated 13 alleles of four genes coding for acid phosphatase, -and -esterases, and malic enzyme. The genes were localized and their positions regarding the centromere are as follows: Acph-1—centromere—Me—cu—dt—-Est—[Inversion 2t]—-Est. The occurrence of crossing-over in Drosophila imeretensis males, as well as the tetrameric structure of malic enzyme, was confirmed.     

The α/β Interfaces of α1β1, α3β3, and F1: Domain Motions and Elastic Energy Stored during γ Rotation

ATP synthase (F_oF₁) consists of F₁ (ATP-driven motor) and F_o (H⁺-driven motor). F₁ is a complex of ₃₃ subunits, and is the rotating cam in ₃₃. Thermophilic F₁ (TF₁) is exceptional in that it can be crystallized as a monomer and an ₃₃ oligomer, and it is sufficiently stable to allow refolding and reassembly of hybrid complexes containing 1, 2, and 3 modified or . The nucleotide-dependent open–close conversion of conformation is an inherent property of an isolated and energy and signals are transferred through / interfaces. The catalytic and noncatalytic interfaces of both mitochondrial F₁ (MF₁) and TF₁ were analyzed by an atom search within the limits of 0.40 nm across the interfaces. Seven (plus thermophilic loop in TF₁) contact areas are located at both the catalytic and noncatalytic interfaces on the open form. The number of contact areas on closed increased to 11 and 9, respectively, in the catalytic and noncatalytic interfaces. The interfaces in the barrel domain are immobile. The torsional elastic strain applied through the mobile areas is concentrated in hinge residues and the P-loop in . The notion of elastic energy in F_oF₁ has been revised. X-ray crystallography of F₁ is a static snap shot of one state and the elastic hypotheses are still inconsistent with the structure, dyamics, and kinetics of F_oF₁. The domain motion and elastic energy in F_oF₁ will be elucidated by time-resolved crystallography.     

A membrane-bound enzyme complex synthesising glucan and glucomannan in pine tissues

Particulate membrane preparations isolated from cambial cells and differentiating and differentiated xylem cells of pine (Pinus sylvestris L.) trees synthesised [¹⁴C]glucans using either guanosine 5-diphosphate (GDP)-D-[U-¹⁴C]glucose or uridine 5-diphosphate (UDP)-D-[U-¹⁴C]glucose as glycosyl donors. Although these glucans had -(13) and -(14) linkages in an approximate ratio 1:1, the distribution of the linkages in the glucan synthesised from GDP-D-glucose was different from that synthesised from UDP-D-glucose. The synthesis of the mixed -(13) and -(14) glucan from GDP-D-[U-¹⁴C]glucose was changed to that of -(14) glucomannan in the presence of increasing concentrations of GDP-D-mannose. The glucan formed from UDP-D-[U-¹⁴C]glucose was not affected by any concentration of GDP-D-mannose. The membrane preparations epimerized GDP-D-glucose to GDP-D-mannose; however, the low amount of GDP-D-mannose formed was not incorporated into the polymer becaus the affinity of the synthase for GDP-D-glucose was much greater than that for GDP-D-mannose. The glucan formed from GDP-D-glucose and the glucomannan formed from GDP-D-glucose together with GDP-D-mannose were characterized. The apparent K _m and V _max of the glucan synthase for GDP-D-glucose were 6.38 M and 5.08 M·min^-1, respectively. No lipid intermediates were detected during the synthesis of either glucan or glucomannan. The results indicated that an enzyme complex for the formation of the glucomannan was bound to the membrane.Abbreviations GDP guanosine 5-diphosphate - GLC gasliquid chromatography - UDP trridine 5-diphosphate     

Development of a shoot regeneration protocol for genetic transformation in <Emphasis Type="Italic">Pelargonium zonale</Emphasis> and <Emphasis Type="Italic">Pelargonium peltatum</Emphasis> hybrids

The attempts of this investigation were to develop a system for plant regeneration from explants of adult plants and its use for genetic transformation of important commercial Pelargonium zonale hybrid and P. peltatum hybrid cultivars. To this aim, leaf blade and petiole explants of eight cultivars were cultured on modified MS (Murashige and Skoog, 1962) medium with two concentrations of TDZ, BA, and zeatin (5 and 20 M). Petiole explants showed a higher regeneration response than leaf blade explants and TDZ was the most effective cytokinin. Petioles of 16 cultivars were incubated on medium containing 5, 10, 15, and 20 M TDZ, respectively, in order to identify the most effective TDZ concentration. For the majority of genotypes 10 M TDZ resulted in the best regeneration response. Cefotaxim at 500 mg l ^–1 had no effect on shoot regeneration and did not show interaction with glufosinate. For selection of transgenic cells, a concentration of 2.5 M glufosinate was shown to be appropriate. LBA4404 and EHA101 Agrobacterium strains carrying pIBGUS vector with pat gene as selectable marker gene and GUS gene as reporter gene were compared in transformation studies. With regard to GUS expression in petiole explants 16 days after coculture, better results were obtained with EHA 101 than with LBA 4404.     

Enzymic synthesis of lacto-N-triose II and its positional analogues

N-acetylhexosaminidase fromNocardia orientalis catalysed the synthesis of lacto-N-triose II glycoside (-d-GlcNAc-(1-3)--d-Gal-(1-4)--d-Glc-OMe,3) with its isomers -d-GlcNAc-(1-6)--d-Gal-(1-4)--d-Glc-OMe (4) and -d-Gal-(1-4)-[-d-GlcNAc-(1-6)]--d-Glc-OMe (5) throughN-acetylglucosaminyl transfer fromN,N-diacetylchitobiose (GlcNAc₂) to methyl -lactoside. The enzyme formed the mixture of trisac-charides3, 4 and5 in 17% overall yield based on GlcNAc₂, in a ratio of 20:21:59. Withp-nitrophenyl -lactoside as an acceptor, the enzyme also producedp-nitrophenyl -lacto-N-trioside II (-d-GlcNAc-(1-3)--d-Gal-(1-4)--d-Glc-OC₆H₄NO₂-p,6) with its isomers -d-GlcNAc-(1-6)--d-Gal-(1-4)--d-Glc-OC₆H₄NO₂-p (7) and -d-Gal-(1-4)-[-d-GlcNAc-(1-6)]--d-Glc-OC₆H₄NO₂-p (8). In this case, when an inclusion complex ofp-nitrophenyl lactoside acceptor with -cyclodextrin was used, the regioselectivity of glycosidase-catalysed formation of trisaccharide glycoside was substantially changed. It resulted not only in a significant increase of the overall yield of transfer products, but also in the proportion of the desired compound6.Abbreviations GlcNAc₂ 2-acetamido-2-deoxy--d-glucopyranosyl-(1-4)-2-acetamido-2-deoxy-d-glucose - NAHase N-acetylhexosaminidase - -CD -cyclodextrin     

Interchange-trisomics in barley

Observations on morphology, sterility and cytology of some interchangetrisomics obtained from the progeny of radiation induced interchangeheterozygotes in a 6-rowed barley (Hordeum vulgare L.) var. K₁₂ are described. The different interchange trisomics show distinct phenotypic expression and have been classified as bushy, slender, robust, semi-erect and pseudonormal on the basis of their gross morphology, leaf characteristics, awn and spike lengths. All interchange trisomics show pollen and ovule sterility which varies between plants. Meiotic behaviour is described. The five different interchange trisomics appear to have different extra chromosomes.     

Effect of ionophores on the processing of theβ-amyloid precursor protein in different cell lines

Summary 1. Alzheimer's disease is characterized by the deposition in the brain of extracellular amyloid plaques and vascular deposits consisting mostly of amyloid-peptide (A). A, a polypeptide of 39–43 amino acids (M _r, 4 kDa), is derived proteolytically from a family of proteins of 695–770 amino acids (M _r, 110–140 kDa) called-amyloid precursor protein (APP).2.APP, an integral membrane glycoprotein, is extensively posttranslationally modified within the endoplasmic reticulum (ER) and various Golgi compartments.APP is cleaved by proteases in either the trans-Golgi network or the post-Golgi apparatus and then secreted as a truncated soluble form into the conditioned media of cultured cells and cerebrospinal fluid samples from human subjects.APP can be processed either by an antiamyloidogenic secretory pathway or by an endosomal/lysosomal pathway.3. I studied the effect of two ionophores on the processing ofAPP in cultured cells. Monensin and, in some cases, ammonium chloride increase the intracellular accumulation ofAPP in several cell lines and may alter its processing. Monensin, which had the most consistent effects, also inhibited secretion ofAPP in a differentiated (growth factor mediated) cell line. Nigericin, with greater K⁺ selectivity, was less able to alter the accumulation and possible processing of the protein.4. These results suggest that the increase in the accumulation of intracellularAPP observed after treating cells with ionophores has some specificity. The selective effect of these ionophores on the metabolism ofAPP may provide a model system to analyze the pathways for studying maturation, secretion, and degradation ofAPP.     

Carotenoid pigments of Stigmatella aurantiaca (Myxobacterales)

Summary In this first article on the carotenoids of Myxobacterales we report on the minor carotenoids of Stigmatella aurantiaca: phytoene, phytofluene, lycopene, -carotene, 4-keto--carotene, 1,2-dihydro-1-hydroxy--carotene, 4-keto-1,2-dihydro-1-hydroxy--carotene, 4-keto-1,2-dihydro-1-hydroxy-torulene, and 1,2,1,2-tetrahydro-1,1-dihydroxy-lycopene. These pigments account for about 10% of total carotenoids.     

Development of high frequency multiple shoot formation in Persian clover (<Emphasis Type="Italic">Trifolium resupinatum</Emphasis> L.)

An efficient and reliable micropropagation system for Persian clover (Trifolium resupinatum L.) was developed using different explants and media. Node, hypocotyl and cotyledonary node explants were cultured on Murashige and Skoog (MS) medium supplemented with combinations of either 6-benzyladenine (BA) and indole-3-butyric acid (IBA) or BA, Kinetin (KIN) and IBA. Direct multiple shoots developed within 6weeks in all explants in most media tested. The best shoot multiplication capacity was obtained from cotyledonary node explants on MS medium containing 7.1M BA and 1M IBA or 14.1M BA and 1M IBA. Elongated shoots were rooted on either MS medium alone or combination with different concentrations of indole-3-butyric acid (IBA), indole-3-acetic acid (IAA) and -naphthaleneacetic acid (NAA). High rooting was achieved in half strength MS medium containing 8M IBA.     

The systematics of Porphyra: character evolution in closely related species

Isozymes, vegetative and reproductive morphology, seasonality, vertical and geographic distributions and chromosomes were compared for six pairs of putative sibling species of Porphyra (P. abbottae/P. torta, P. fallax subsp. fallax/P. fallax subsp. conwayae, P. amplissima/P. cuneiformis, P. fucicola/P. leucostica, P. miniata/P. variegata, P. umbilicalis/P. umbilicalis) and among five species in a complex (P. brumalis, P. kurogii, P. linearis, P. pseudolinearis, and P. purpurea.) Geographic distribution and zymograms for certain proteins showed the greatest change between species pairs: only one pair of species had identical distributions, and most species pairs were disjunct; every species had a different allozyme for GOT-1, whereas all species had apparently identical proteins for phycoerythrin. Seasonality and habitat exhibited moderate differentiation: Northeast Pacific sibling species were characterized by a high intertidal winter species pairing with a mid intertidal spring species, whereas all but one of the other species pairs exhibited nearly identical vertical distributions and seasonalities. There were few changes in morphology: most species pairs had essentially identical morphologies and coloration and the same arrangement of reproductive cells. Chromosome numbers and karyotypes were identical for species pairs and in the species complex. These results provide evidence for different rates of evolution of different characters in the genus Porphyra.     

The glycolipid specificity ofErythrina cristagalli agglutinin

The interaction of¹²⁵I-labeledErythrina cristagalli agglutinin (ECA) with neutral glycosphingolipids on thin layer chromatograms was examined by the overlay technique followed by radioautography. The lectin bound topara-globoside with a sensitivity about 10 times higher than to lactosylceramide or globoside, in agreement with the specificity of the lectin forN-acetyllactosamine. The lower limit of detection ofpara-globoside was about 0.66 nmol. The specific binding of ECA to this glycolipid was confirmed by a highly sensitive enzyme-linked lectin assay (ELLA), utilizing the horseradish peroxidase-avidin-biotin system for detection of bound lectin. Overlays of neutral glycosphingolipid extracts from human erythrocyte membranes and from human granulocytes with ECA demonstrated that the lectin can be employed for the detection of small amounts ofpara-globoside in biological materials also in the presence of excess globoside. No staining was obtained when thin layer chromatograms of neutral glycosphingolipid extracts from rabbit erythrocyte membranes were overlayed with¹²⁵I-ECA. Afterin situ treatment of the chromatograms with -galactosidase, the lectin bound to several components, one of which had a mobility corresponding to that of the pentahexosylceramide Gal3Gal4GlcNAc3Gal4Glc1Cer, the major neutral glycosphingolipid of rabbit erythrocytes, thus providing further evidence for the specificity of ECA forpara-globoside.Abbreviations GSL glycosphingolipid(s) - CDH lactosylceramide, Gal4Glc1Cer - CTH trihexosylceramide, Gal4Gal4Glc1Cer - GLOB globoside, GalNac3Gal4Gal4Glc1Cer - PG para-globoside, Gal4GlcNAc3Gal4Glc1Cer - AsG_M1 asialo-G_M1, Gal3GalNAc4Gal4Glc1Cer - FORS Forsmann antigen, GalNAc3GalNAc3Gal4Gal4Glc1Cer - CPH pentahexosylceramide, Gal3Gal4GlcNAc3Gal4Glc1Cer - ECA Erythrina cristagalli agglutinin - SBA soybean agglutinin - PBS phosphate-buffered saline - PVP-40 polyvinylpyrrolidone M.W. 40000 - BSA bovine serum albumin - HRP-avidin horseradish peroxidase conjugated to avidin - ELLA enzyme-linked lectin assay - ELISA enzyme-linked immunosorbent assay - PMNL polymorphonuclear leukocytes - HPTLC high performance thin layer chromatography     

A Cytogenetic Study of the Leaf Beetle Genus Cyrtonus (Coleoptera, Chrysomelidae)

The chromosomes of ten species of Cyrtonus and the genome sizes of six are surveyed. Among the total of 15 chromosomally studied species, 11 have 2n=28 chromosomes and a 13+Xy_p male meioformula, three have 2n=40 and 19+Xy_p and one 2n=46 and 22+Xy_p. All but one species with 28 chromosomes show only metacentric or submetacentric chromosomes, whereas the species with 40 and 46 chromosomes display some telocentrics or subtelocentrics, that are probably derived from the former by centric fissions. However, since the number of major chromosome arms is strikingly higher in these latter species (NF=70 and 78) than in the 28-chromosome species (mostly NF=56), other chromosomal rearrangements such as pericentric inversions or heterochromatin accretions could also be involved. The genome sizes display a narrow range, from 1C=0.6–1.22pg, and they are not significantly correlated with the chromosome numbers. Some possible factors implied in the rough chromosomal evolution of Cyrtonus are discussed in relation to a few other genera of the subfamily Chrysomelinae.     

Comparison of laboratory- and field-derived soil water retention curves for a fine sand soil using tensiometric,resistance and capacitance methods

The approximate range from 100 to 50% of plant-available water in Apopka fine sand (loamy, siliceous, hyperthermic Grossarenic Paleudult) is 0.08–0.04 cm³ cm^–3 soil water content () or –5 to –15 kPa of soil water matric potential (). This narrow range of plant-available soil water is extremely dry for most soil water sensors. Knowledge of the soil water retention curves for these soils is important for effective irrigation of crops in fine sand soils of subtropical and tropical regions of the world. The primary objective of this study was to compare sandy soil water retention curves in the field as measured by tensiometer and resistance block values and capacitance sensor . The second objective was to compare these curves to one developed on a Florida fine sand soil using a pressure plate apparatus. Tensiometer and resistance block values were compared to values from capacitance sensors calibrated gravimetrically. The effective range of both tensiometers and resistance sensors in fine sand soils is between –5 and –20 kPa . Soil water potential values for both sensors were within 2 kPa of the mean for each sensor. Change in was similar over the range of 0.04–0.08 cm³ cm^–3 . Curves for the two sensors were different by 4 kPa at 0.04 cm³ cm^–3. The relationship between and were similar at 10–20, 20–30 and 40–50 cm depths. This was not true for a laboratory determined soil water retention curve for the same soil type. These differences are significant in soils with very low water holding capacities. Differences between laboratory- and field-determined retention curves could be due to a combination of entrapped air in the field soil and/or alteration in bulk density in the laboratory samples.     

Transformation of yeast and Podospora: innocuity of senescence-specific DNAs

Summary Two senscence-specific DNAs (sen-DNAs and ) were tested for their ability to drive autonomous replication in yeast and Podospora. The but not the sequence has autoreplicative (ARS) properties in yeast; the ARS sequences of are not included in the region common to all the sen-DNAs. Neither the nor the sequences can confer autoreplicative properties in Podospora. These sequences inserted into a hybrid vector carrying the suppressor tRNA, su4-1, do not change the mode of transformation of a suppressible leu-1-1 strain of Podospora: the transformation is by integration whether or not the plasmid carries a sen-DNA sequence. The su4-1 gene integrates at its homologous site in a minority of cases. It is possible to reisolate free plasmids at a low frequency from some transformants. The presence of a sen-DNA on the transforming vector has no effect upon the longevity of the transformants.