Ultrastructural evidence of GABA-ergic inhibition and glutamatergic excitation in the pacemaker nucleus of the gymnotiform electric fish,Hypopomus

The medullary pacemaker nucleus of Hypopomus triggers each electric organ discharge (EOD) by a single command pulse. It consists of electrotonically coupled pacemaker cells, which generate the rhythm, and relay cells, which follow the pacemaker cells and excite the spinal motoneurons of the electric organ. The pacemaker cells receive two inputs from the complex of the diencephalic prepacemaker nucleus (PPn), a GABA-ergic inhibition and a glutamatergic excitation. Relay cells, on the other hand, receive two glutamatergic inputs, one from a subnucleus of the PPn, the PPn-C, and a second from the sublemniscal prepacemaker nucleus (SPPn).We have labelled afferents to the pacemaker nucleus by injecting HRP to specific sites of the prepacemaker complex. By using immunogold-labelled antibodies and en-grid staining techniques, we demonstrated GABA and glutamate immunoreactivity in labelled synaptic profiles of ultra-thin sections of the pacemaker nucleus. The two types of synapses were interspersed on the surfaces of pacemaker cells, with GABA-immunoreactive synapses apparently representing the GABA-mediated input of the PPn-I, an inhibitory subdivision of the PPn, and glutamate-immunoreactive synapses representing the input of the PPn-G, an excitatory subdivision of the PPn. Only glutamate-immunoreactive synapses were found on relay cells.Abbreviations AMPA -Amino-3-hydroxy-5-methylisoxazole-4-propionic acid - CP central posterior nucleus - EOD electric organ discharge - GABA -aminobutyric acid - GAD L-glutamate decarboxylase - HRP horseradish peroxidase - JAR jamming avoidance response - NMDA N-methyl-D-aspartate - PPn (diencephalic) prepacemaker nucleus - SPPn sublemniscal prepacemaker nucleus     

Observations on the fine structure of the cercaria of Notocotylus attenuatus and formation of the cyst wall of the metacercaria

Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells.     

Recombinant Components of the EcoRII Restriction–Modification System: Restriction Endonuclease Can Interact with DNA · RNA Duplexes

To obtain recombinant restriction endonuclease (R) and methylase (M) of the EcoRII restriction–modification system, bacterial strains overproducing their functional hexahistidine derivatives were constructed. Active full-length R·EcoRII was produced only in cells that also expressed M·EcoRII from a multicopy plasmid. Recombinant R·EcoRII bound with hybrid DNA·RNA duplexes.     

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     

A propos des ≪chloride cells≫ dans l'épithélium des lamelles branchiales du poisson rouge

Résumé L'ultrastructure des lamelles branchiales et spécialement celle des chloride cells du poisson rouge (Carassius aureus) a été étudiée. Nous avons constaté que du matériel amorphe floconneux, faiblement adiélectronique était attaché aux endroits des creux apicaux. Afin de préciser la nature de ce matériel, nous avons étudié ces structures au microscope électronique avec les techniques suivantes: acide periodique méthènamine d'argent, colorations au fer colloïdal et au bleu d'alcian. Après la réaction à l'acide periodique méthènamine d'argent, de fines précipitations aux endroits des creux apicaux, correspondant au matériel floconneux visible après la fixation au glutaraldéhyde tétroxyde d'osmium, étaient visibles. La coloration au bleu d'alcian révélait des particules fortement colorées formant un film plus ou moins continu à la surface libre des lamelles, sauf aux endroits oò les chloride cells sont en contact avec la surface. Là et notamment dans les 2reux apicaux, du matériel légèrement granuleux, de faible densité, faisait une couche assez épaisse attachée à la membrane cellulaire. Tenant compte des résultats d'autres auteurs et de nos propres observations, nous considérons que la plus grande partie du matériel se trouvant à la surface des chloride cells, et particulièrement dans les creux apicaux, est de type glycoprotéique.

---

The ultrastructure of the chloride cells in the gill epithelium of the goldfish

Summary The ultrastructure of the secondary lamellae of the gills and especially that of the chloride cells of Carassius aureus was studied. We found an amorphous, flakey, slightly adielectronic material in the areas of the apical pits. In order to determine the nature of this material, we studied these structures electronmicroscopically applying the periodic acid silver methenamine, colloidal iron and alcian blue methods. The periodic acid silver methenamine reaction, resulted in finely dispersed precipitations which were deposited in the areas of the apical pits and which correspond to the flakey material seen in the ordinary electron micrographs. The alcian blue method reveales strongly stained particles which form a more or less continuous film on the free surface of the lamellae, interrupted only at the level of the chloride cells. In these areas, notably within the apical pits, a rather thick layer of finely granular low-density material is attached to the plasma membrane. In taking into account other studies performed on this subject, as well as our own observations, we consider the material found on the surface of the chloride cells and particularly within their apical pits to be predominantly of glycoproteinous nature.

---

---

Dédié à Monsieur le Professeur Dr Ernst Horstmann, Hambourg, à l'occasion de son soixantième anniversaire.     

The temperature-dependent duration of development and parasitism of three cereal aphid parasitoids, Aphidius ervi, A. rhopalosiphi, and Praon volucre

Temperature dependencies were established for the egg-to-mummy and mummy-to-adult phases, for mummy mortality, and for parasitism of Aphidius ervi Haliday, Aphidius rhopalosiphi De Stefani-Perez, and Praon volucre (Haliday) (Hymenoptera, Aphidiidae), three parasitoids of Sitobion avenae (Fabricius) (Homoptera, Aphididae), at 8°C, 12°C, 16°C, 20°C, and 25°C on winter wheat (cv. Haven). A physiological model described temperature-dependent development over the full temperature range, whereas a linear model was fitted for data above 8°C and used to estimate the lower temperature thresholds and day-degrees (° D) required for development. The thresholds for A. ervi were 2.2°C for egg-mummy development and 6.6°C for mummy-adult development, those for A. rhopalosiphi were 4.5°C and 7.2°C, and those for P. volucre were 3.8°C and 5.5°C. The time to develop into mummies and adults differed significantly between the three species: A. ervi development into mummies required an average of 159 ° D, while development into adults took an average of 73 ° D. The corresponding average times required for A. rhopalosiphi and P. volucre to develop mummies were 124° D and 126° D, while their development into adults required an average of 70° D and 150° D, respectively. Mummy mortality was 25–35% at 8°C and less at the higher temperatures tested, but began to increase again at 25°C, showing a quadratic relationship between mortality and temperature. Parasitization was very low or, in the case of P. volucre, absent up to 12°C and thereafter increased with increasing temperature. The relationship between parasitization, recorded as percent aphids mummified, and temperature was linear at the temperatures tested and depended on species. A. ervisuperparasitized 11.1% aphids at 20°C and 16.6% aphids at 25°C, whereas superparasitism was low in A. rhopalosiphi and absent in P. volucre. From 16°C to 25°C the P. volucre sex ratio increased. For A. ervi and A. rhopalosiphi there was no trend with temperature, but at 20°C and 25°C it was close to even. Field data for 1996 and 1997 allowed for a comparison of actual and expected emergence of overwintering mummies. In both years, parasitoids were predicted to have emerged from overwintering mummies well in advance of the onset of aphid infestation, and more than a month earlier than the first parasitized aphids were found in winter wheat. Observations from trap plants in other crops supported the predictions of the models. Other factors that can affect biological control by cereal aphid parasitoids are discussed.     

Purification and immunocytochemical localization of kafirins inSorghum bicolor (L. Moench) endosperm

Summary Kafirins are the storage proteins of sorghum and are found in protein bodies in the seed endosperm. They have been classified as -, -, and -kafirins according to differences in molecular weight, solubility, and structure. The kafirins were purified, amino acid composition was determined, and immunolocalization methods were used to determine the organization of the protein bodies and distribution of kafirins throughout the endosperm. All three groups of kafirins were low in lysine. -Kafirins and -kafirins were relatively high in cysteine, and -kafirins were relatively high in methionine. Transmission electron microscopy showed that protein bodies in the peripheral endosperm were spheroid with concentric rings and few darkly stained inclusions. In contrast, protein bodies of the central endosperm were irregularly shaped with a higher proportion of darkly stained material. The light staining regions of the protein bodies are composed primarily of -kafirins with minor portions of - and -kafirins. The dark staining regions, however, are composed primarily of - and -kafirins. Immunoelectron microscopy showed that protein bodies in the peripheral endosperm contain predominantly a-kafirin with minor amounts of - and -kafirin. Central endosperm protein bodies are also predominantly -kafirin, but have a higher proportion of -kafirin and -kafirin than the peripheral endosperm protein bodies.Abbreviations GAR-HRP Goat anti-rabbit horseradish peroxidase - IgG immunoglobulin G - 2-ME 2-mercaptoethanol - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis - TBS Tris buffer saline - TBS-T Tris buffer saline with Tween - TBS-T-B Tris buffer saline with Tween and bovine serum albumin - TCA trichloroacetic acid - UV ultraviolet     

Carotenoid pigments in a red strain of Rhizobium from Lotononis bainesii Baker

The carotenoid pigments of a Rhizobium strain isolated from Lotononis bainesii were found to be diglucosyl-4,4-diapocarotene-4,4-dioate and glucosyl-4,4-diapocarotene-4-oate-4-oic acid.5th publication in the series Carotenoids of Rhizobia [4th publication: Helv. chim. Acta 62: 2551–2557 (1979)]     

AKIN<Emphasis Type="Italic">β</Emphasis>3, a plant specific SnRK1 protein,is lacking domains present in yeast and mammals non-catalytic <Emphasis Type="Italic">β</Emphasis>-subunits

The SNF1/AMPK/SnRK1 heterotrimeric kinase complex is involved in the adaptation of cellular metabolism in response to diverse stresses in yeast, mammals and plants. Following a model proposed in yeast, the kinase targets are likely to bind the complex via the non-catalytic -subunits. These proteins currently identified in yeast, mammals and plants present a common structure with two conserved interacting domains named Kinase Interacting Sequence (KIS) and Association with SNF1 Complex (ASC), and a highly variable N-terminal domain. In this paper we describe the characterisation of AKIN3, a novel protein related to AKIN subunits of Arabidopsis thaliana, containing a truncated KIS domain and no N-terminal extension. Interestingly the missing region of the KIS domain corresponds to the glycogen-binding domain (-GBD) identified in the mammalian AMPK1. In spite of its unusual features, AKIN3 complements the yeast sip1sip2gal83 mutant. Moreover, interactions between AKIN3 and other AKIN complex subunits from A. thaliana were detected by two-hybrid experiments and in vitro binding assays. Taken together these data demonstrate that AKIN3 is a -type subunit. A search for -type subunits revealed the existence of 3-type proteins in other plant species. Furthermore, we suggest that the AKIN3-type subunits could be plant specific since no related sequences have been found in any of the other completely sequenced genomes. These data suggest the existence of novel SnRK1 complexes including AKIN3-type subunits, involved in several functions among which some could be plant specific.     

Micropropagation of mature Chinese tallow tree (Sapium sebiferum Roxb.)

An in vitro propagation technique based on axillary bud proliferation has been developed for matureSapium sebiferum trees. Nodal segments cultured on Murashige and Skoog (MS) medium supplemented with benzyl adenine (1–10 m and -naphthaleneacetic acid (0–0.5 m showed axillary bud proliferation. Shoots proliferated in vitro were multiplied on Murashige and Skoog medium containing 2.5 m benzyl adenine and 0.25 m -naphthaleneacetic acid. Seasonal changes affected the shoot proliferation potential of the initial explant. Shoots were rooted on a half-strength, growth-regulator-free, agar-gelled, MS medium after a 48-h treatment on half-strength MS liquid medium with 10 m indole-3-butyric acid. Rooted plantlets were potted and acclimatized in a growth chamber and then moved to the greenhouse. Four-month-old plants were transplanted to the field.Abbreviations BA Benzyl adenine - IBA Indole-3-butyric acid - 2-ip N⁶-(-dimethylallylamino)purine - MS Murashige and Skoog (1962) medium - NAA -Naphthaleneacetic acid     

Toxicity and neuronal transport of stable liposomes and phospholipid in the nervous system

When unilamellar stable liposomes composed of a dialkyl analog of phosphatidylcholine, tetradecyloctadec-11-eno(1)phosphocholine (dialkyl-PC), plus cholesterol at 11 molar ratio, and a trace of [³H]dialkyl-PC were injected into the vitreous of the rabbit eye, macrophage infiltration and phagocytosis of lipid were observed in retina including the epiretinal myelinated nerve fiber bundles, with no other neurotoxic effects. Little or no incorporation of [³H]dialkyl-PC was observed in the distal tissues of the optic system. With labile vesicles composed of egg lecithin, trace amounts of [³H]dialkyl-PC, and phosphatidic acid, no morphological changes occurred. After a lag of more than 7 days [³H]dialkyl-PC appeared in superior colliculus, indicating axonal transport of the lipid in an anterograde direction. Experiments with submandibular and parotid gland indicated retrograde transport of the lipid. The data do not suggest axonal transport of intact (stable) liposomes, but suggest that intact phospholipid molecules can be axonally transported.     

The occurrence of caulonema-specific proteins in different moss species

Soluble proteins extracted with Tris-buffer pH 8.8 from different mosses are analysed by microgelelectrophoretic method for comparison to the specific proteins present only in the caulonema of Funaria hygrometrica. The protein patterns are also compared with those of liverwort, fern gametophytes and sporophytes and tobacco. It is observed that the caulonema specific proteins are only present in the caulonema of these mosses and are absent in other plants.Abbreviations CSP caulonema specific proteins     

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.     

Trace metal contamination initiates the apparent auto-aggregation,amyloidosis, and oligomerization of Alzheimer’s Aβ peptides

Nucleation-dependent protein aggregation (seeding) and amyloid fibril-free formation of soluble SDS-resistant oligomers (oligomerization) by hydrophobic interaction is an in vitro model thought to propagate -amyloid (A) deposition, accumulation, and incur neurotoxicity and synaptotoxicity in Alzheimers disease (AD), and other amyloid-associated neurodegenerative diseases. However, A is a high-affinity metalloprotein that aggregates in the presence of biometals (zinc, copper, and iron), and neocortical A deposition is abolished by genetic ablation of synaptic zinc in transgenic mice. We now present in vitro evidence that trace (0.8 µM) levels of zinc, copper, and iron, present as common contaminants of laboratory buffers and culture media, are the actual initiators of the classic A1–42-mediated seeding process and A oligomerization. Replicating the experimental conditions of earlier workers, we found that the in vitro precipitation and amyloidosis of A1–40 (20 µM) initiated by A1–42 (2 µM) were abolished by chelation of trace metal contaminants. Further, metal chelation attenuated formation of soluble A oligomers from a cell-free culture medium. These data suggest that protein self-assembly and oligomerization are not spontaneous in this system as previously thought, and that there may be an obligatory role for metal ions in initiating A amyloidosis and oligomerization.     

Polygonal inequalities as a key to neuronic equations

Neuronic or decision equations, first proposed as a mathematical model of neural activity, have shown, after their exact, compact solution was found, typical behaviours that make them natural tools for General Systems studies. It is shown here that their mathematical investigation is remarkably furthered by generalizing the triangular inequality to polygonal ones. These permit the immediate computation of the tensorial expansion of linearly separable boolean functions, and exhibit clearly the connection between their continuous and discontinuous aspects.     

Expression of the plant sulphite reductase in cell suspension cultures from Catharanthus roseus L.

Sulphur-heterotrophic growth exhibited a dual response to the expression of sulphate-assimilating enzymes. The level of ATP-sulphurylase (EC 2.7.7.4) appeared repressed while sulphite reductase (EC 1.8.7.1) and O-acetyl-l-serine sulphhydrylase (EC 4.2.99.8) were derepressed and coordinated in their occurrence. The capability of the cells to reduce adenylylphosphosulphate or 3-phospho adenylylphosphosulphate to cysteine coincided with the activity of sulphite reductase. The expression of these reducing steps lacked correlation with the regulation of ATP-sulphurylase.Abbreviations APS adenylylphosphosulphate - MVH reduced methylviologen - OAS O-acetyl-l-serine - PAPS 3-phospho adenylylphosulphate     

Qualitative and quantitative composition of pigments in Phaeodactylum tricornutum (Bacillariophyceae) stressed by iron

The effect of Fe(III) deficiency on qualitative and quantitative changes in pigment composition in Phaeodactylum tricornutum Bohlin was demonstrated by HPLC and AAS. Maximum content of pigments showed the diatom cells incubated at the optimum iron concentration, i.e., 10 M. The contents of chlorophyll a, chlorophyll c ₁+c ₂, fucoxanthin, diadinoxanthin and ,-carotene were 109.99, 20.16, 40.39, 1.29 and 1.48 fg per cell, respectively. The results obtained showed that Fe(III) affected qualitative and quantitative pigment composition in P. tricornutum. The content of individual pigments, proportions between accompanying pigments and their ratios to chlorophyll a were important indicators of phytoplankton response to iron stress. The strong reduction in ,-carotene content, several times (2–5) increase in diadinoxanthin level as compared to ,-carotene, and high amount of diadinoxanthin in relation to chlorophyll a were observed in algae growing at very low Fe(III) concentrations, 0.001 and 0.01 M. The data suggested that phytoplankton pigments could be a potential physiological marker.     

Untersuchungen über die Ultrastruktur der Gonaden von Chironomus (Dipt.)

Zusammenfassung Im Ovar von Chironomus sind in Phase 1 des 4. Larvenstadiums polygonal abgeflachte Innenzellen von kleineren Außenzellen umgeben, die Bakteroide und Phagosomen enthalten; zwischen den Innenzellen liegen unregelmäßige Zelltrümmer (keimbahnbegleitende Substanzen). Zu Beginn der Ovariolenbildung werden in Phase 3 durch Spalträume zwei Schichten der Außenzellen voneinander getrennt, von denen die innere (Follikel- und Eikanalepithel) regelmäßige Buchten bildet. In diese Buchten wandern von innen Zellpaare ein, die an synaptischen Komplexen bzw. multiplen Chromatinstrukturen als Ei- und Nährzellen kenntlich sind. Zwischen beiden Zellen sind Fusome häufig, die später in eigentümlicher Weise geschlossen werden. Zwischen den Eikanalzellen entsteht in Phase 5 durch Spaltbildung der Eikanal; in Phase 7 sind die Eikanalzellen auffallend glykogenreich. Kurz vor der Vitellogenese treten im Bereich der Oocyte Membransysteme und annulated lamellae auf; akzessorische Kerne werden als Ausstülpungen des Oocytenkernes gebildet und später abgeschnürt. In Phase 9 sind an der Peripherie der Eizelle Mikrovillisäume und Pinocytosebläschen sichtbar. Die distalen Zellen der Ovariole haben Eioder Nährzellcharakter, sind aber bei Ch. melanotus nicht von Follikelzellen umgeben und werden beim weiteren Ovariolenwachstum reduziert. Trotz extrem geringer Nährzellzahl der Follikel scheint das Chironomus-Ovar funktionell nicht von anderen polytroph meroistischen Insektenovarien unterschieden.

---

Ultrastructure of Chironomus (Dipt.) gonads1. Normal development of ovaries during the fourth larval instar

Summary In the ovary of Chironomus during phase 1 of the fourth larval instar, polygonally flattened inner cells are surrounded by smaller outer cells which contain bacteroids and phagosomes. Irregular cell remnants (germ line accompanying substances) lie among the inner cells. At the beginning of ovariole formation in phase 3, two layers of outer cells are separated by the formation of fissures. The inner layer of these cells (follicle- and egg-passage epithelium) forms regular invaginations. Cell pairs, identified as oocytes and nurse cells by synaptic complexes or multiple chromatin structures, wander from inside into the invaginations. Frequently between the two cells are fusomes, which later close in a characteristic manner. During phase 5, an egg passage is formed as a fissure among the egg-passage cells. During phase 7, the egg passage cells are conspicuously full of glycogen. Shortly before vitellogenesis membrane systems and annulated lamellae appear in the region of the oocyte. Accessory nuclei are formed by a tieing-off of projections of the the oocyte nucleus. During phase 9, microvilli and pinocytotic vesicles can be seen at the periphery of the oocyte. The distal cells of the ovariole are of oocyte or nurse cell nature, but in Ch. melanotus they are not surrounded by follicle cells and are reduced during further ovariole growth. In spite of the extremely small number of nurse cells in the follicle, the Chironomus ovary apparently does not differ functionally from other polytrophic meroistic insect ovaries.

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Binding of Amyloid Beta-Protein to Intracellular Brain Proteins in Rat and Human

Amyloid beta-protein (A), in its soluble form, is known to bind several circulatory proteins such as apolipoprotein (apo) E, apo J and transthyretin. However, the binding of A to intracellular proteins has not been studied. We have developed an overlay assay to study A binding to intracellular brain proteins. The supernatants from both rat and human brains were found to contain several proteins that bind to A 1–40 and A 1–42. No major difference was observed in the A binding-proteins from brain supernatants of patients with Alzheimer's disease and normal age-matched controls. Binding studies using shorter amyloid beta-peptides and competitive overlay assays showed that the binding site of A to brain proteins resides between 12–28 amino acid sequence of A. The presence of several intracellular A-binding (AB) proteins suggests that these proteins may either protect A from its fibrillization or alternatively promote A polymerization. Identification of these proteins and their binding affinities for A are needed to assess their potential role in the pathogenesis of Alzheimer's disease.     

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.