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.     

Bi-antennary oligo-(N-acetyllactosamino)glycans of I-type are galactosylated preferentially at the GlcNAcβ1-6Gal linked arms by α1,3-galactosyltransferase of bovine thymus

1,3-Galactosylation of radiolabelled bi-antennary acceptors Gal1-4GlcNAc1-3(Gal1-4GlcNAc1-6)Gal-R (R=1-OH, 1-4GlcNAc or 1-4Glc) with bovine thymus 1,3-galactosyltransferase was studied. At all stages of the reactions the three acceptors reacted faster at the 1 6 linked arm than at the 1 3 linked branch. Hence, in addition to the doubly 1,3-galactosylated products, practically pure Gal1-4GlcNAc1-3(Gal1-3Gal1-4GlcNAc1-6)Gal-R could be obtained from the three acceptors in reactions that had proceeded to near completion. The isomeric mono-1,3-galactosylated products were identified by using exoglycosidases to remove the branches unprotected by 1,3-galactoses and by subsequently identifying the resulting linear glycans chromatographically.Abbreviations Gal d-galactose - GlcNAc N-acetyl-d-glucosamine - Lac lactose - LacNAc Gal1-4GlcNAc - MH maltoheptaose - MP maltopentaose - MT maltotriose - MTet maltotetraose - WGA wheat germ agglutinin - 3 position 3 of the galactose unit of LacNAc or Lac - 6 position 6 of the galactose unit of LacNAc or Lac     

Ultrastructure of lycopene containing chromoplasts in fruits ofAglaonema commutatum schott (Araceae)

Summary The ripening process in fruits ofA. commutatum is characterized by clearly distinguishable developmental stages of their pericarp plastids. With respect to predominant pigments and ultrastructural features the following scheme is proposed: 1. The green stage with a tendency to thylakoid degeneration and plastoglobule formation leads to 2. the yellow stage. An increasing number of globules, mostly being membrane associated, are converted to tubules. In this stage, the main pigments are -carotene and cryptoxanthine. The development of membraneous invaginations from the inner plastid envelope leads to 3. the red stage. Concomitantly with lycopene synthesis and incorporation, these envelope-derived membranes expand and become electron dense (after KMnO₄ treatment), but maintain their triple-layered structure. Chromoplasts of deep red coloured fruits (1,400 g lycopene g^–1 dry wt) contain lycopene crystals within the lumina of membraneous sacs which are also derived from the inner envelope membrane. The molar ratio between the three main pigments -carotene, cryptoxanthine, and lycopene is about 1110 in this final state. GA/OsO₄ fixation is unable to stabilize the lycopenic structures (membranes as well as crystals).     

High D-glucose does not affect binding of α-tocopherol to human erythrocytes

The role of -tocopherol uptake system in human erythrocyte in the uptake of plasma -tocopherol has been suggested. However no information is available on -tocopherol uptake activity of human erythrocytes in the presence of high levels of D-glucose which is known to lead to pathological alterations in different cells including human erythrocytes. Therefore, in order to examine the effect of D-glucose on the binding of -tocopherol to human erythrocytes, the binding characteristics of -tocopherol to these cells were established first. Binding of [3H]-tocopherol to human erythrocytes was both saturable and specific. Scatchard analysis of -tocopherol binding to these cells showed the presence of two independent classes of binding sites with widely different affinities. The high affinity binding sites had a dissociation constant (Kd1) of 90 nM with a binding capacity (n1) of 900 sites per cell, whereas the low affinity binding sites had a dissociation constant (Kd2) of 5.2 M and a binding capacity (n2) of 105,400 sites per cell. Trypsin treatment abolished all the -tocopherol binding activity. Competition for the binding of -tocopherol to human erythrocytes was effective with other homologues of -tocopherol (-tocopherol, -tocopherol and -tocopherol) and their potency was almost equal to -tocopherol itself. The order of preference was -tocopherol > -tocopherol -tocopherol -tocopherol. Incubation of human erythrocytes with various concentrations of D-glucose did not affect -tocopherol uptake activity. Our data demonstrate the presence of an -tocopherol uptake system in human erythrocytes and that the -tocopherol uptake activity is not modulated by the presence of D-glucose.     

Genetic variation detected by use of the M13 “DNA fingerprint” probe in Malus,Prunus, and Rubus (Rosaceae)

Summary Recently, DNA fingerprints have been reported in a wide array of organisms. We used the M13 repeat probe on several genera and species in the angiosperm family Rosaceae. Four apple cultivars could be differentiated when any one of five restriction enzymes was used to analyze minisatellite DNA. Similarly, four individual trees of Prunus serotina (black cherry) exhibited different fingerprints with each of four enyzmes. A total of 14 Rubus (blackberries and raspberries) plants representing four species were investigated with two enzymes. Extensive inter-and intraspecific variation was found. However, some closely growing plants had identical fingerprints, probably due to their being derived through vegetative propagation.     

Binding of the galactose-specificPseudomonas aeruginosa lectin,PA-I,to glycosphingolipids and other glycoconjugates

The carbohydrate-binding specificity ofPseudomonas aeruginosa lectin I (PA-I) in iodinated or biotinylated form was studied. A large number of glycosphingolipids, as well as some glycoproteins and neoglycoproteins were used as ligands. Also, inhibition by free saccharides of PA-I binding to glycosphingolipids was tested. It was found that the lectin binds most strongly to terminal and nonsubstituted Gal3Gal- or Gal4Gal-structures.Abbreviations PA-I Pseudomonas aeruginosa lectin I - Cer ceramide - lactosylceramide Gal4GlcCer - iso globotriaosylcerami Gal3Gal4GlcCer - globotriaosylceramide Gal4Gal4GlcCer - globoside or globotetraosylceramide GalNAc3Gal4Gal4GlcCer - Forssman glycolipid GalNAc3GalNAc3Gal4Gal4GlcCer - P1 glycolipid Gal4Gal4GlcNAc3Gal4GlcCer - lactoneotetraosylceramide Gal4GlcNAc3Gal4GlcCer - B5 glycolipid Gal3Gal4GlcNAc3Gal4GlcCer - gangliotetraosylceramide Gal3GalNAc4Gal4GlcCer - GM1 Gal3GalNAc4(NeuAc3)Gal4GlcCer - RBC red blood cells - BSA bovine serum albumin - PBS phosphate-buffered saline - SDS sodium dodecyl sulfate - TLC thin-layer chromatography - HPLC high pressure liquid chromatography - MS mass spectrometry - FAB fast-atom bombardment - EI electron impact     

The linear tetrasaccharide,Galβ1-4GlcNAcβ1-6Galβ1-4GlcNAc,isolated from radiolabeled teratocarcinoma poly-N-acetyllactosaminoglycan resists the action ofE. freundii endo-β-galactosidase

A novel linear tetrasaccharide, Gal1-4GlcNAc1-6Gal1-4GlcNAc, was isolated from partial acid hydrolysates of metabolically labeled poly-N-acetyllactosaminoglycans of murine teratocarcinoma cells. It was characterized by exo-glycosidase sequencing and by mild acid hydrolysis followed by identification of all partial cleavage products. The tetrasaccharide, and likewise labelled GlcNAc1-6Gal1-4GlcNAc, resisted the action of endo--galactosidase (EC 3.2.1.103) fromE. freundii at a concentration of 125 mU/ml, while the isomeric, radioactive teratocarcinoma saccharides Gal1-4GlcNAc1-3Gal1-4GlcNAc and GlcNAc1-3Gal1-4GlcNAc were cleaved in the expected manner.Abbreviations WGA wheat germ agglutinin - BSA bovine serum albumin - [³H]GlcNAc1-4-GlcNAc1-4GlcNAcOL N,N,NN'-triacetylchitotriose reduced with NaB³H₄     

A model of associative memory in the brain

A model of associative memory for time varying spatial patterns is proposed and simulated on a digital computer. This is a network composed of many neuron-like elements, and shows an ability for associative memory similar to that of the brain.Suppose a number of sequences of spatial patterns are presented to this network, for example, 12345, ABC, and so on. Then, these patterns are memorized in the network. After that, if any part of one of these sequences, say 23, is presented to the circuit, the rest of the sequence, 45, is recalled following to it. It resembles to such a situation — if we hear a part of a melody which we have memorized in the past, the rest of the melody is recalled even after it is stopped half-way. Although the recalled patterns are not always 100% correct, they are not completely destroyed even if the presented patterns are imperfect.     

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.     

Synthesis of selectively radiolabeled hexasaccharides for the determination of enzymatic regioselectivity

Poly-N-acetyllactosamines provide backbone structures for functional modifications such as sialyl Lewis X. To understand how the biosynthesis of poly-N-acetyllactosamines is regulated, two branched oligosaccharides of the structure Gal1,4GlcNAc1, 6(Gal1,4GlcNAc1,2)-Man1,6Man-octyl 1 and 2 were synthesized in which one of the terminal galactose units was selectively radiolabeled. Hexasaccharides 1 and 2 were assembled from the chemically synthesized pentasaccharide precursors GlcNAc1,6(Gal1,4GlcNAc1,2)-Man1,6Man-octyl3 and Gal1,4GlcNAc1,6(GlcNAc1, 2) - Man1,6 Man-octyl 4 respectively, through treatment with UDP-1-[³H]-Gal and 1,4 galactosyltransferase. Compounds 1 and 2 were subsequently incubated with UDP-GlcNAc and the UDP-GlcNAc: Gal1-4Glc(NAc)1,3-N-acetylglucosaminyltransferase (i-GlcNAc transferase) resulting in a partial conversion to a mixture of heptasaccharides which were purified by HPLC. The branch selectivity of the addition of N-acetylglucosamine to compounds 1 and 2 was then characterized by endo--galactosidase digestion of the heptasaccharides, followed by isolation of the resultant pentasaccharides on C18 reverse-phase silica cartridges. Comparison of the amount of radiolabel to a control reaction lacking endo--galactosidase indicated the favored site of GlcNAc addition to be the lower 1,2-branch over the 1,6-branch by a 3:1 ratio.     

Regio- and stereo-selective synthesis of vinyl glucose ester catalyzed by an alkaline protease of Bacillus subtilis

The transesterification of -d-glucose with divinylsuccinate, divinyladipate and divinylsebacate in pyridine at 55 °C for 3 days was catalyzed by an alkaline protease from Bacillus subtilis to give corresponding 6-O-vinyl glucose esters at 30%, 53% and 35% yield, respectively. The stereo-selectivity of the alkaline protease toward the -anomer was affected by the acyl donor chain length. 6-O-Vinylsuccinyl-d-glucose was mixture of - and -anomers (/=44/56), the other two products were the pure -d-glucose derivatives.     

Sialidase of swine influenza A viruses: variation of the recognition specificities for sialyl linkages and for the molecular species of sialic acid with the year of isolation

The sialidase of swine influenza A viruses of N1 and N2 subtypes, isolated from 1930 to 1992, was studied for substrate specificity with ganglio-series, lacto-series type II and GM3 gangliosides containing Neu5Ac2-3Gal, Neu5Gc2-3Gal and Neu5Ac2-6Gal linkages. All viral sialidases tested showed that the activity for hydrolysing substrates with Neu5Ac2-3Gal was higher than the activities with Neu5Gc2-3Gal and Neu5Ac2-6Gal linkages. When GM1b, GM3 and sialylparagloboside were used as substrates, the earliest strain (A/Wisconsin/15/30 H1N1, isolated in 1930) showed the activity ratio of Neu5Ac2-6Gal to Neu5Ac2-3Gal to be 0.13:0.2, and the ratio Neu5Gc2-3Gal/Neu5Ac2-3Gal to be 0.19:0.37, while those strains isolated from 1978 to 1992 exhibited ratios of 0.29:0.58 for Neu5Ac2-6Gal/Neu5Ac2-3Gal and 0.51:0.76 for Neu5Gc2-3Gal/Neu5Ac2-3Gal. The above results indicate that the substrate specificities of sialidases from swine influenza A viruses towards sialyl linkages and the molecular species of sialic acid are related to the year of isolation, i.e. strains isolated after 1978 exhibited higher activity towards Neu5Ac2-6Gal and Neu5Gc2-3Gal linkages when compared with strains isolated in an earlier year, 1930.Abbreviation Neu5Ac 5-N-acetylneuraminic acid - Neu5Gc 5-N-glycolyneuraminic acid - Gal d-galactose - Glc d-glucose - Cer Ceramide - II³(Neu5Ac)Lac Neu5Ac2-3Gal1-4Glc - GM3(Neu5Ac2-3Gal) Neu5Ac2-3Gal1-4Glc1-Cer - GM3(Neu5Gc2-3Gal) Neu5Gc2-3Gal1-4Glc1-Cer - GM1b(Neu5Ac2-3Gal) Neu5Ac2-3Gal1-3GalNac1-4Gal1-4Glc1-Cer - GMlb(Neu5Gc2-3Gal) Neu5Gc2-3Gal1-3GalNAc1-4Gal1-4Glc1-Cer - IV³(Neu5Ac)nLc4Cer Neu5Ac2-3Gal1-3GlcNAc1-4Gal1-4Glc1-Cer - IV³(Neu5Gc)nLc4Cer Neu5Gc2-3Gal1-3GlcNAc1-4Gal1-4Glc1-Cer - IV⁶(Neu5Ac)nLc4Cer Neu5Ac2-6Gal1-3GlcNAc1-4Gal1-4Glc1-Cer - TDC taurodeoxycholate.     

Uptake of sewage derived nitrogen by<Emphasis Type="Italic"> Ulva rigida</Emphasis> (Chlorophyceae) in Bahía Nueva (Golfo Nuevo,Patagonia, Argentine)

Uptake kinetics of nitrogen derived from sewage–seawater mixtures (2.5–20% v/v effluent) were determined in the laboratory for Ulva rigida (Chlorophyceae) native from Bahía Nueva (Golfo Nuevo, Patagonia, Argentine). In terms of nitrogen concentration, experimental enrichment levels varied between 53.7 and 362.3M of ammonium and between 0.77 and 6.21M of nitrate+nitrite. Uptake rates were fitted to the Michaelis–Menten equation, with the following kinetic parameters: ammonium: V_max = 591.2molg^–1h^–1, K _s=262.3M, nitrate+nitrite: V _max=12.9molg^–1h^–1, K _s=3.5M). Both nutrients were taken up simultaneously, but ammonium incorporation was faster in all cases. The results show a high capability of Ulva rigida to remove sewage-derived nitrogen from culture media. In the field, most of the nitrogen provided by the effluent would be tied up in algal biomass, supporting low nitrogen levels found at a short distance away from the source.     

Diversity of the mouse T cell receptor Cγ1 gene: structural analysis in C57BL/Ka

We have isolated an unusual T cell receptor chain cDNA clone (7.1) from a library made from RNA derived from adult thymus of C57BL/Ka mice. This cDNA clone corresponds to the appropriately processed C1 constant region exons preceded by 1.5 kb of J-C1 intron. The 7.1 coding region is extremely homologous to the C1 gene of BALB/c mice, differing at the protein level by a single deletion (alanine 139) and a single substitution. This latter change eliminates the sole N-linked sugar attachment site, providing a basis for strain-specific glycosylation patterns. The J-C1 intronic region contains two DNA segments (termed J1 and J2) that are highly reminiscent of joining (J) segments; both have potentially functional recombination and donor splice sequences flanking an open reading frame. Northern analysis suggests that 7.1 may be derived from a large, variable region-containing precursor.     

Polarities in Mammalian Evolution Seen Through Homologs of the Inner Cell Mass

Embryogenetic pathways differ markedly among monotremes, marsupials, and placentals, and their analysis provides information of fundamental importance to recognition of mammalian evolutionary directions. The cap of cuboidal cells of the marsupial late unilaminar blastocyst, generally known as the embryonic area, probably is induced to form (prior to origin of Hensen's node) by signals from earliest hypoblastic cells (anterior visceral endoderm). The thickened cap is a medullary plate of sauropsid terminology because it includes epiblastic cells presumptive to neurectoderm (including neural crest), Hensen's node, primitive streak, and gut endoderm. The remainder of the definitive embryo (i.e., parts of epidermal origin, including ectodermal placodes) derives from squamous ectoderm (surrounding the medullary plate) of the blastocyst's ill-named trophoblastic area. Amniotic ectoderm develops farther distally within the trophoblastic area. The autapomorphic inner cell mass (ICM) of placental mammals is homologous to medullary plate of the marsupial blastocyst plus morphologically undefined, proximal parts of surrounding ectoderm (of the trophoblastic area). Considerations of early cell lineages in marsupials are greatly affected by recognition that the boundary between future embryonic and extra-embryonic tissues does not match the margin of the medullary plate (i.e., embryonic area). Marsupials and monotremes largely conform to sauropsid early embryogenesis, but placentals express, at earliest developmental stages, innovations unique within Amniota that are linked to early establishment of the brain. Neonatal marsupials and hatchling monotremes are extremely altricial and closely comparable anatomically/physiologically; they share a temporal pattern in combining early morphogenesis of craniofacial features (related to suckling) with deferral of telencephalic completion into postnatal/posthatching life. Placentals contrast greatly in establishing the central nervous system prior to rudiments of the cranial skeleton and associated musculature, and they complete essentials of forebrain development before birth. Comparative evidence from transitory periderm suggests that primordial eutherians had extremely altricial hatchlings or newborns, whichever was the mode of early development. Details remain unknown about the origin of the unique specialization of ICM plus encapsulating trophoblast from the more generalized blastula of ancestral synapsids.     

Carbohydrate antigen expression in murine embryonic stem cells and embryos. II. Sialylated antigens and glycolipid analysis

Summary A mouse embryonic stem (ES) cell line E14 and early mouse embryos were stained with a panel of 15 monoclonal antibodies recognizing sialylated or potentially sialylated carbohydrate determinants, Sialyl Le-x and sialyl Le-a were detected on the pre-implantation embryo from the 8-cell stage, and sialyl Le-a weakly on undifferentiated ES cells. Changes in cell surface carbohydrates occurred after induction of ES cell differentiation with retinoic acid (RA) and dibutyryl cAMP. Qualitative analysis of the neutral glycolipids of untreated and RA-treated ES cells using high-performance thin-layer chromatography (HPTLC) revealed few differences between the two types of culture. The major gangliosides in both cultures were indicative of an active a ganglioside synthesis pathway. GD₃, a precursor of the b synthesis pathway, previously reported to be characteristic of embryonal carcinoma (EC) cells, was absent. RA-induced differentiation caused a shift in the spectrum to more complex gangliosides. Application of fast atom bombardment mass spectrometry (FAB-MS) to permethylated derivatives of individual bands permitted partial characterization of an unusual sialylated glycolipid and a rare ganglioside with the suggested structure of GalNAc-GD1a.Abbreviations NeuAc N-acetylneuraminic acid - Cer ceramide - CMH monohexosylceramide - CDH lactosylceramide (Gal1-4Glc1-Cer) - CTH ceramide trihexoside (Gal1-4Gal1-4Glc1-Cer) - globoside (GalNAc1-3 Gal1-4Gal1-4Glc1-Cer) - Forssman antigen (GalNAc1-3GalNAc1-3Gal1-4Gal1-4Glc1-Cer) - GM₃ (NeuAc2-3Gal1-4Glc1-Cer) - GD₃ (NeuAc2-8NeuAc2-3Gal1-4Glc1-Cer) - GM1 (Gal1-3GalNAc1-4[NeuAca2-3]Gal1-4Glc1-Cer) - GD1a (NeuAc2-3Gal1-3GalNAc1-4[NeuAc2-3]Gal1-4Glc1-Cer) - GT1b (Neu5Ac2-3Gal1-3GalNAc1-4[Neu5Ac2-8Neu5Ac2-3]Gal1-4Glc1-Cer) The glycolipids are named according to Svennerholm (1963) and the recommendations of the IUPAC-IUB Commission on Biochemical Nomenclature (1978).     

Structural and Functional Features of the Escherichia coli F 1 -ATPase

The structural organization and overall dimensions of the Escherichia coli F₁-ATPase in solutionhas been analyzed by synchroton X-ray scattering. Using an independent ab initio approach,the low-resolution shape of the hydrated enzyme was determined at 3.2 nm resolution. Theshape permitted unequivocal identification of the volume occupied by the _{3 3} complex ofthe atomic model of the ECF₁-ATPase. The position of the ^ and subunits were found byinteractive fitting of the solution scattering data and by cross-linking studies. Laser-inducedcovalent incorporation of 2-azido-ATP established a direct relationship between nucleotidebinding affinity and the different interactions between the stalk subunits and with the threecatalytic subunits () of the F₁-ATPase. Mutants of the ECF₁-ATPase with the introductionof Trp-for-Tyr replacement in the catalytic site of the complex made it possible to monitorthe activated state for ATP synthesis (ATP conformation) in which the and subunits arein close proximity to the subunits and the ADP conformation, with the stalk subunits arelinked to the subunit.     

Silver nitrate and aminoethoxyvinylglycine affect <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated apple transformation

In Fuji, the production of ethylene was increased with the addition of AgNO₃ and inhibited with the addition of 10 M aminoethoxyvinylglycine (AVG). The addition of 80 M AgNO₃ to transformed explants of Fuji cultured on selection medium resulted in increased ethylene production (20 l l^–1) at 3 weeks. Under examining the effect of AgNO₃ in Fuji, the 40 M AgNO₃ showed with higher 33.8% and 6.5% in the efficiency of regeneration and transformation. However, ethylene production in Gala explants treated with 10M AgNO₃ (3 l l^–1) decreased after 2 weeks compared with the control (5 l l^–1). Although the regeneration efficiency of Gala with 10 M AgNO₃ was higher (41.1%) than the control (20.1%), there was no significant difference in the transformation efficiency at the same concentration. Shoot regeneration of Fuji and Gala was completely inhibited with 10 M AVG. These results suggest that the addition of AgNO₃ affects the efficiency of Agrobacterium-mediated gene transfer in Fuji.Eun Soo Seong, Ill Min Chung- These two Authors Contributed equally to this work     

Ultrastructure and behaviour of the spindle pole body of the aphid-pathogenic fungusErynia neoaphidis

Summary A detailed account of the ultrastructure and behaviour of the spindle pole body (SPB) of the entomophthoraceous fungusErynia neoaphidis is presented for the first time.The SPB consists of extranuclear (ENC) and intranuclear (INC) components. The ENC is a saucepan-shaped structure which lies in a pocket of the nuclear envelope. It is composed of a forked, fibrillar handle and a shallow, cylindrical pan. The pan has a wall of two layers, both of which are thickened with a regular periodicity so that they appear to be beaded. It is postulated that the pan is formed from rough endoplasmic reticulum and that it synthesizes the amorphous, electron-dense material coating the ENC.The INC is a saucer-shaped, electron-dense plaque in which the ends of the spindle microtubules terminate. During metaphase, a clear zone separates the INC from the nuclear envelope and persists until telophase. The roles of the amorphous, electron-dense material and the clear zone as well as the method of SPB replication are discussed.     

?kologische untersuchungen an aphiden

Zusammenfassung In Temperaturkabinen wird die Fortpflanzungspotenz von Myzus persicae (Sulzer) (Herkunft Groß-Lüsewitz) bei Dauertemperaturen von 15 bis 30° auf Kohlrüben (Brassica napus subspec. rapifera) untersucht.Eine Populationsanalyse nach Birch (1948) (intrinsic rate of increase) ergab den höchsten Wachstumsfaktor bei Dauertemperaturen zwischen 20 und 23°.Dauertemperaturen >25° führten zu einer starken Minderung der. Fortpflanzungspotenz. 30° ist die obere Grenze der Fortpflanzung der untersuchten Myzus persicae-Population.

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The reproductive potential of the peach-potato aphid (origin Gross-Lüsewitz) was studied at temperatures between 15° and 30° in constant temperature chambers. They were cultivated on Swede (Brassica napus spp. rapifera) which stood in Knop's nutrient under gauze cloches in petri dishes. The production of juvenile larvae and the mortality of the mothers was measured daily. The total of all larvae (including those which were dropped) and the total of larvae on the leaf were separately enumerated. The larvae on the leaf were designated as viable larvae. A population analysis using Birch's method showed a maximum value for the growth factor k (difference between birth and mortality rates) of 23° for the total of all larvae, and of 20° for the viable larvae (Fig. 6). The daily relative growth-ratio was at the same temperatures respectively 1.36 and 1.34 (Table IV). Optimum development of M. persicae on swedes occurs thus between 20° and 23°. The percentages of viable larvae which add to the net production of total larvae are 53, 61, 30, and 24 (Table III) at temperatures of 15, 20, 25, and 30° respectively. The average length of a generation was 18.5 days at 15° and less than 13 days at 28 to 30° (Fig. 5). The multiplication rate per generation was 38 at 15°, 48 at 20°, but only 5.5 at 30° (Fig. 4). The time of development from first-stage larva to adult was 12.5 days at 15°, 5 days at 28° and 6 days at 30° (Table VII). The upper limit, where a weak multiplication was still possible, was at 30°. It is concluded that in regions where such limiting temperatures occur during some part of the day, the temperature can be the major regulating factor of the insect populations.