A vascular network closely linked to the epithelium of the urinary bladder of the rat

Summary Scanning electron microscopy was used on the mucosa of the rat urinary bladder after digestion with strong alkali and microdissection. The underside of the epithelium (and the plane of the epithelium-tunica propria interface) is not smooth but is scored by grooves-10 m wide and 3–4 m deep—connected into a fine mesh. A net of blood capillaries located in the uppermost part of the tunica propria occupies these grooves. They measure 3–9 m in diameter, are separated from the epithelium by a gap of 0.3 m, often show fenestrations, and are accompanied by numerous and extensive pericytes and by some fibroblasts. We discuss these observations in the light of current knowledge of blood flow in the bladder, contraction and distension of the bladder wall and formation of mucosal folds, transport of solutes through the epithelium, and plasma extravasation from mucosal blood vessels in neurogenic inflammation.     

Male reproductive effect of arsenic in mice

Arsenic, a known human carcinogen, was given to mice via drinking water as sodium arsenite at a dose 53.39, 133.47, 266.95 and 533.90 mol l for 35 days. A decrease in the activity of 17 HSD along with increase in LDH, GT activity were observed at 533.90 mol l. The observed sperm count, motility and morphological abnormalities in sperm were similar to control at lower dose levels. However at 533.90 mol l a significant decrease in sperm count and motility along with increase in abnormal sperm were noticed. Significant accumulation of arsenic in testes and accessory sex organs may be attributed to the arsenic binding to the tissues or greater cellular uptake. No effects were observed on indices studied for reproductive effects at 53.39 mol l arsenic close to which human being are exposed through drinking water under the present set of experimental conditions.     

Morphology and structural organization of spiracles in femaleArgas (Persicargas) walkerae (Acari: Argasidae)

Scanning electron microscopical investigations of fractures and corrosion casts of the spiracles from femaleA. walkerae ticks revealed a four-part structure, consisting of spiracular plate, ostium and macula forming the external closure, followed by the subostial space and the vestibulum of regulable volume, as well as the atrial chamber as the innermost part from which the main tracheal trunks originate. On the average, the spiracular plate was 158 m long and 188 m at the broadest width. It consisted of a thin, highly perforated external and a thick internal layer, which enclosed the interpedicellar space with numerous stout pedicels. In its posterior region, the spiracular plate was covered by the macula, which was up to 80 m in length and 110 m in width. The interpedicellar cavity opened into the subostial space measuring 95.5 m in length and 159.6m in width, which proceeded into the 112-m long vestibulum. The roof of the vestibulum was flexible and could be everted and inverted. Inverted, the roof formed a quadratic bulge with numerous deep cuticular folds, which confined the lumen of the vestibulum either partially or completely. In corrosion casts, the roof was everted to a length of up to 89.3 m. In the posterior part of the vestibulum, as well as in the initial fourth of the artrial chamber, numerous anvil-, cone-or drop-like cuticular projections were arranged in wedge-like fashion. The atrial chamber was almost spherical with a diameter of 138.4 m. Five main tracheal trunks of different luminal diameter as well as numerous channels opened into the atrial chamber.     

Aspects of carbon and nitrogen cycling in soils of the Bornhöved Lake district II. Modelling the influence of temperature increase on soil respiration and organic carbon content in arable soils under different managements

Based on field measurements in two agriculturalecosystems, soil respiration and long-term response ofsoil organic carbon content (SOC) was modelled. Themodel predicts the influence of temperature increaseas well as the effects of land-use over a period ofthirty years in a northern German glacial morainelandscape. One of the fields carried a maizemonoculture treated with cattle slurry in addition tomineral fertilizer (maize monoculture), the otherwas managed by crop rotation and recieved organicmanure (crop rotation). The soils of both fieldswere classified as cambic Arenosols. The soilrespiration was measured in the fields by means of theopen dynamic inverted-box method and an infrared gasanalyser. The mean annual soil respiration rates were 268 (maizemonoculture) and 287 mg CO₂ m^-2 h^-1(crop rotation). Factors controlling soil respirationwere soil temperature, soil moisture, root respirationand carbon input into the soil. Q₁₀-valuesof soil respiration were generally higher in winterthan in summer. This trend is interpreted as anadaptive response of the soil microbial communities.In the model a novel mathematical approach withvariable Q₁₀-values as a result oftemperature and moisture adjustment is proposed. Withthe calibrated model soil respiration and SOC werecalculated for both fields and simulations over aperiod of thirty years were established. Simulationswere based on (1) local climatic data, 1961 until1990, and (2) a regional climate scenario for northernGermany with an average temperature increase of 2.1 K.Over the thirty years period with present climateconditions, the SOC pool under crop rotation wasnearly stable due to the higher carbon inputs, whereasabout 16 t C ha^-1 were lost under maizemonoculture. Under global warming the mean annualsoil respiration for both fields increased and SOCdecreased by ca. 10 t C ha^-1 under croprotation and by more than 20 t C ha^-1 undermaize monoculture. It was shown that overestimationof carbon losses in long-term prognoses can be avoidedby including a Q₁₀-adjustment in soilrespiration models.     

Nonspecific (“pseudo-plasmal”) dye-binding in the Feulgen nuclear stain and its blocking by azocarmin G

Summary In Feulgen nuclear staining nonspecific dye-binding due to the pseudo-plasmal reaction is intensified in isolated cells with intact cytoplasm, and cannot be eliminated by the post-irradiation method. Fluorescence intensity in the cytoplasm sometimes exceeds that of specific nuclear fluorescence, especially in brain and heart muscle cells, and it was almost impossible to perform cytofluorometric DNA quantification on such specimens. Various kinds of aldehyde-blocking agents such as sodium borohydride, 2,4-dinitrophenylhydrazine, aniline, and sodium pyrosulfite were effective in reducing the pseudo-plasmal reaction. But the blocking effects were not complete because of additional release of reactive aldehyde groups during subsequent Feulgen hydrolysis. Acidic azocarmin G produces a complete block of all pseudo-plasmal reaction in acriflavine-Feulgen nuclear staining, allowing accurate DNA-cytofluorometry to be carried out.     

CO2 gas exchange of benthic microalgae during exposure to air: a technique for the rapid assessment of primary production

A method of measuring CO₂gas exchange (caused, for example, by microalgal photosynthesis on emersed tidal mudflats) using open flow IR gas analyzers is described. The analyzers are integrated in a conventional portable photosynthesis system (LI-6400, LI-COR, Nebraska, USA), which allows manipulation and automatic recording of environmental parameters at the field site. Special bottomless measuring chambers are placed directly on the surface sediment. Measurements are performed under natural light conditions and ambient CO₂concentrations, as well as under different CO₂concentrations in air, and various PAR radiation levels produced by a LED light source built into one of the measurement chambers. First results from tidal channel banks in a north Brazilian mangrove system at Bragança (Pará, Brazil) under controlled conditions show a marked response of CO₂assimilation to CO₂concentration and to irradiance. Photosynthesis at 100molmol^–1CO₂in air in one sample of a well-developed algal mat was saturated at 309mol photons m^–2s^–1, but increased with increasing ambient CO₂concentrations (350 and 1000mol mol^–1CO₂) in the measuring chamber. Net CO₂assimilation was 0.8mol CO₂m^–2s^–1at 100mol mol^–1CO₂, 5.9mol CO₂m^–2s^–1at 350mol mol^–1CO₂and 9.8mol CO₂m^–2s^–1at 1000mol mol^–1CO₂. Compensation irradiance decreased and apparent photon yield increased with ambient CO₂concentration. Measurements under natural conditions resulted in a quick response of CO₂exchange rates when light conditions changed. We recommend the measuring system for rapid estimations of benthic primary production and as a valuable field research tool in connection with certain ecophysiological aspects under changing environmental conditions.     

Identification of two RAPD markers tightly linked with the Nicotiana debneyi gene for resistance to black root rot of tobacco

Linkage of randomly amplified polymorphic DNA (RAPD) markers with a single dominant gene for resistance to black root rot (Chalara elegans Nag Raj and Kendrick; Syn. Thielaviopsis basicola [Berk. and Broome] Ferraris) of tobacco (Nicotiana tabacum L.), which was transferred from N. debneyi Domin, was investigated in this study. There were 2594 repeatable RAPD fragments generated by 441 primers on DNAs of Delgold tobacco, a BC₅F₈ near isogenic line (NIL) carrying the resistance gene in a Delgold background, and PB19, the donor parent of the resistance gene. Only 7 of these primers produced eight RAPD markers polymorphic between Delgold and PB19, indicating there are few RAPD polymorphisms between them despite relatively dissimilar pedigrees. Five of the eight RAPD markers were not polymorphic between Delgold and the NIL. All of these markers proved to be unlinked with the resistance gene in F₂ linkage tests. Of the remaining three RAPD markers polymorphic between Delgold and the NIL, two were shown to be strongly linked with the resistance gene; one in coupling and the other in repulsion. Application of the two RAPDs in the elimination of linkage drag associated with the N. debneyi resistance gene and marker-assisted selection for the breeding of new tobacco cultivars with the resistance gene is discussed.     

Untersuchungen zur Regulation der Bacteriochlorophyll-Synthese bei Rhodospirillum rubrum

Zusammenfassung Wenn Rhodospirillum rubrum aus aeroben Dunkelkulturen in ein synthetisches Medium übertragen und anaerob im Licht bebrütet wird, beginnt die Bacteriochlorophyllbildung bereits nach 1 Std, das Wachstum erst nach 5–8 Std Bebrütung. — Puromycin (10 g/ml) und Chloramphenicol (20 g/ml) hemmen in diesen Kulturen Protein- und Pigmentsynthese vollständig. Eine Hemmung wird auch beobachtet, wenn die Antibiotica erst mehrere Stunden nach Beginn der Lichtbebrütung zugesetzt werden. Synthese von Thylakoidprotein und Bacteriochlorophyll scheinen regulatorisch gekoppelt zu sein.Actinomycin C (D) (40 g/ml) und Mitomycin (1 g/ml) hemmen die Bacteriochlorophyllbildung enbenfalls. Die Thylakoidbildung ist vom Vorhandensein einer funktionsfähigen DNS und RNS abhängig.Die spezifische Aktivität der -Aminolaevulinsäuresynthetase nimmt in anaeroben Lichtkulturen gegenüber aeroben Dunkelkulturen um etwa das Vierfache zu. Sie wird durch die verwendeten antibiotica nicht beeinflußt. Die Biosynthese des Enzyms wird durch Mitomycin und Puromycin, nicht aber durch Actinomycin gehemmt.

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Summary If dark-aerobically grown Rhodospirillum rubrum is transferred to anaerobic conditions in the light, the synthesis of photosynthetic pigments starts after 1 or 2 hours. The growth of the culture begins in the synthetic medium not before 5 hours incubation. In these cultures Puromycin (10 g/ml) and Chloramphenicol (20 g/ml) inhibit synthesis of protein and bacteriochlorophyll both. An inhibition is also observed when the antibiotics are added some hours after the beginning of anaerobic light incubation.The synthesis of chromatophore protein and bacteriochlorophyll are likely connected by gen-regulation.Actinomycin C (D) (40 g/ml) and Mitomycin C (1 g/ml) inhibit the bacteriochlorophyll synthesis likewise. The effect of actinomycin is increased by preincubation with the antibiotic in the dark. Mitomycin C stops synthesis of bacteriochlorophyll and protein even if it added after preincubation in the light.The level of -aminolevulinic acid-synthetase increased fourfold in anaerobic light-cultures compared to dark-aerobically grown cells. The activity of the enzyme is not influenced by the antibiotics. But the rate of biosynthesis is inhibited by Puromycin and Mitomycin, but not by Actinomycin.

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Abkürzungen im Text ALS -Aminolaevulinsäure - B-Chlorophyll Bacteriochlorophyll - DNS Desoxyribonucleinsäure - RNS Ribonucleinsäure     

Production of glucosamine containing disaccharides of the Lewis-A and -X types employing glycosidases

Disaccharide derivatives of interest for inhibition studies and for synthesis of the blood group determinants Lewis-a and Lewis-x were obtained with glycosidases as catalysts. Thus, Fuc(1–4)(6-OBn)GlcNH₂SEt and Gal1–3(6-OBn)GlcNH₂-SEt were produced employing (6-OBn)GlcNH₂SEt as acceptor and -L-fucosidase and -D-galactosidase, respectively, as catalysts. The phthalimido derivative of lactosamine, Gal1-4GlcNPhthSEt, was prepared from lactose employing GlcNPhthSEt as the acceptor and a yeast -galactosidase as catalyst. The reactions were both regio- and stereospecific, which allowed straightforward production of pure products on a g scale and higher.     

Axillary shoot induction and plant regeneration in Plantago ovata Forssk

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

Enzyme-catalyzed synthesis of alkyl β-D-glycosides with crude homogenate ofSulfolobus solfataricus

Summary Crude homogenate of thermophilic archaebacteriumSulfolobus solfataricus, possessing a -glycosidase, has been used to synthesize different alkyl -D-glycosides starting from phenyl -D-glucoside, phenyl -D-galactoside and lactose as carbohydrate donors. High product yield (95% with respect to the carbohydrate donor) of octyl -D-glucoside has been obtained in a two-phase system containing 5% of water. The enantioselection for the galactosyl transfer to the secondary hydroxyl group of propane-1,2-diol is higher than that found using -galactosidase fromE. coli.     

Hormonal regulation of hepatic glycogenolysis inAmphibolurus nuchalis,the western netted dragon: an in vitro study

Summary In mammals hepatic glycogenolysis is controlled by several hormones using cyclicAMP, Ca²⁺ and/or diacylglycerol as intracellular messengers. In contrast, in teleost fish, lungfish and amphibians fewer hormones promote hepatic glycogenolysis, and cyclicAMP is the sole intra-cellular messenger. This suggests that the -adrenergic mechanism became associated with the liver after amphibians separated from the vertebrate line. Reptiles separated later, and the aim of this study is to elucidate the hormonal control of hepatic glycogenolysis in a reptile,Amphibolurus nuchalis, and especially to determine which adrenergic receptor system is operative.InA. nuchalis liver pieces cultured in vitro, adrenaline and glucagon stimulated glycogen breakdown and glucose release, glycogen phosphorylase activity and accumulation of cyclicAMP in the tissue. Neurohypophysial peptides did not affect these parameters. These actions of adrenaline were completely blocked by the -adrenergic antagonist, propranolol and slightly reduced by the -adrenergic antagonist, phentolamine. Removal of Ca²⁺ from the medium and addition of the Ca²⁺ chelator, EGTA, did not block the actions of adrenaline, and the Ca²⁺ ionophore A23187 did not mimic these actions.The -adrenegic ligand [¹²⁵I]-iodocyanopindolol (ICP) bound specifically to an isolated membrane preparation fromA. nuchalis liver with a calculated K_D of 100 pM and a Bmax of 37.6 fmol·mg protein^–1. The adrenergic ligands propranolol, isoprenaline, adrenaline, noradrenaline, phenylephrine and phentolamine displaced ICP with K_D's of 20 nM, 1 M, 4.5 M, 32 M, 35 M and 500 M, respectively. The ₂-adrenergic ligand yohimbine did not bind specifically to the membrane, but at 1 nM and 100 pM, specific binding of the ₁-adrenergic ligand prazosin was 45% of total with a mean of 11.3 fmoles·mg protein^–1 specifically bound.These findings indicate that the glycogenolytic actions of adrenaline are mediated primarily via -adrenergic receptors inA. nuchalis, but that -adrenergic receptors may also play some role in the control of hepatic metabolism.     

Purification and characterization of flavone-specific β-glucuronidase from callus cultures of Scutellaria baicalensis Georgi

-Glucuronidase from callus cultures of Scutellaria baicalensis Georgi was purified to apparent homogeneity by fractionated ammonium-sulfate precipitation and chromatography on diethylaminoethyl-cellulose, hydroxylapatite and baicalin-conjugated Sepharose 6B. A 650-fold purification was obtained by this purification system. When subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis the purified protein migrated as a single band with a molecular mass of 55 kDa. We determined that the native enzyme has a molecular mass of 230 kDa using gel-filtration chromatography. These results suggested that the enzyme exists as a homotetramer composed of four identical 55-kDa subunits. The enzyme showed a broad pH optimum between 7.0 and 8.0. The K _m values were 9 M, 10 M, 30 M and 40 M for luteolin 3 -O--d-glucuronide, baicalin, wogonin 7-O--d-glucoronide and oroxlin 7-O--d-glucuronide, respectively. The enzyme was most active with flavone 7-O--d-glucuronides.Abbreviations BA N⁶-benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - pI isoelectric point - R _t retention time     

Phenylacetic acid-induced somatic embryogenesis in cultured hypocotyl explants of geranium (Pelargonium x hortorum Bailey)

Summary The effect of a non-indole compound, phenylacetic acid (PAA), on the induction of somatic embryogenesis in tissue cultures of geranium (Pelargonium x hortorum Bailey cv. Scarlet Orbit Improved) was investigated. Hypocotyl explants derived from young, dark-grown seedlings were cultured on Murashige and Skoog (1962) medium (MS) supplemented with PAA or IAA (0.01–120 M) alone or in combination with BAP (8 M). Somatic embryogenesis was induced by both PAA and IAA at 0.01–20 M with 8 M BAP, however, the optima differed considerably for the two compounds. Maximal activity of IAA for somatic embryogenesis was found at 0.1–2.5 M, whereas PAA gave best results at 10 and 20 M under identical culture conditions. Higher concentrations (30–120 M) of IAA or PAA in the medium induced callusing in the explants, but the callus was neither embryogenic nor morphogenic.Abbreviations BAP N⁶-benzylaminopurine - IAA indole-3-acetic acid - MS Murashige and Skoog (1962) - PAA phenylacetic acid     

Choline Administration Reverses Hypotension In Spinal Cord Transected Rats: The Involvement of Vasopressin

Intracerebroventricular (i.c.v.) choline (50–150 g) increased blood pressure and decreased heart rate in spinal cord transected, hypotensive rats. Choline administered intraperitoneally (60 mg/kg), also, increased blood pressure, but to a lesser extent. The pressor response to i.c.v. choline was associated with an increase in plasma vasopressin. Mecamylamine pretreatment (50 g; i.c.v.) blocked the pressor, bradycardic and vasopressin responses to choline (150 g). Atropine pretreatment (10 g; i.c.v.) abolished the bradycardia but failed to alter pressor and vasopressin responses. Hemicholinium-3 [HC-3 (20 g; i.c.v.)] pretreatment attenuated both bradycardia and pressor responses to choline. The vasopressin V1 receptor antagonist, (-mercapto-, -cyclopenta-methylenepropionyl¹, O-Me-Tyr², Arg⁸)-vasopressin (10 g/kg) administered intravenously 5 min after choline abolished the pressor response and attenuated the bradycardia-induced by choline. These data show that choline restores hypotension effectively by activating central nicotinic receptors via presynaptic mechanisms, in spinal shock. Choline-induced bradycardia is mediated by central nicotinic and muscarinic receptors. Increase in plasma vasopressin is involved in cardiovascular effects of choline.     

Laser kinetic spectroscopy studies of the bimolecular oxygenation of alpha- and beta-subunits within the R-state of human hemoglobin

Bimolecular oxygenation of tri-liganded R-state human hemoglobin (HbA) is described by bi-exponential kinetics with association rate constants k = 27.2 ± 1.3 (M·sec)^-1 and k = 62.9 ± 1.6 (M·sec)^-1. Both the observed processes have been assigned to the bimolecular oxygenation of - and -subunits of the native tetrameric protein by molecular oxygen. The quantum yields of photodissociation within the completely oxygenated R-state HbA are = 0.0120 ± 0.0017 and = 0.044 ± 0.005 for - and -subunits, respectively. The oxygenation reactions of isolated ^PCMB- and ^PCMB-hemoglobin chains are described by mono-exponential kinetics with the association rate constants k = 44 ± 2 (M·sec)^-1 and k = 51 ± 1 (M·sec)^-1, respectively. The quantum yields of photodissociation of isolated ^PCMB- and ^PCMB-chains (0.056 ± 0.006 and 0.065 ± 0.006, respectively) are greater than that observed for appropriate subunits within the R-state of oxygenated HbA.     

Process parameters and reusability of the free cell mass of Torulaspora delbrueckii for the production of L-phenylacetylcarbinol (L-PAC)

The effect of process parameters on the biotransformation of benzaldehyde to L-phenylacetylcarbinol (L-PAC) using a yeast isolate identified as Torulaspora delbrueckii was studied. The maximum yield of L-PAC obtained was (331 mg) per 100 ml biotransformation medium (glucose 3%, peptone 0.6% and at pH 4.5) from 600 mg of benzaldehyde with 8 h of reaction at 30 ± 2 °C. Growing the organism in presence of 3% glucose reduced the biotransformation time to 120 min. Addition of 0.6% acetaldehyde (30–35%) lead to an increase in L-PAC yield to 450 mg%. Semi-continuous feeding of benzaldehyde (200 mg) and acetaldehyde (200 l) four times at 30 min intervals could produce 683 mg of L-PAC/100 ml biotransformation medium. Chiral HPLC analysis of purified L-PAC and PAC-diol showed 99% enantiomeric purity. The cell mass was found to be reusable for biotransformation up to nine times when benzaldehyde and acetaldehyde levels were maintained at (350 mg and 350 l)–(400 mg and 400 l). At concentrations from 450 mg and 450 l to 600 mg and 600 l, however the cell mass could give efficient biotransformation only during one use.     

Zur Feinstruktur der Elektrozeptorepidermis der Mormyridae (Teleostei,Pisces)

Zusammenfassung Die schwachelektrischen Mormyridae haben eine dreischichtige Epidermis, deren innere Schicht aus nur etwa 0,22 m dicken sechseckigen Zellen von ca. 60 m Durchmesser besteht. Die etwa 2 m dicken, linsenförmigen Kerne von 7,6 m Durchmesser liegen am Zellrand. Die Zellen sind zu Säulen aufgeschichtet. Ihr Rand ist ausgezackt und dort, wo er die Säulengrenze erreicht, auf etwa 0,34 m verdickt. In der Nähe der Säulengrenzen sind die Zellen über Desmosomen mit den Nachbarn in der eigenen und in der angrenzenden Säule verbunden. Diese Epidermisschicht ist auf die Körperpartien beschränkt, in denen auch Elektrorezeptoren ausgebildet sind.Die beiden anderen Epidermisschichten haben den üblichen Aufbau einer Fischepidermis, abgesehen vom Fehlen der Becherzellen.

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Ultrastructure of the electroceptor epidermis of the Mormyridae (Teleostei, Pisces)

Summary The weakly electric fish of the family Mormyridae have a three layered epidermis, with a medium layer consisting of hexagonal cells of only 0.22 m in thickness and about 60 m in diameter. The lens-shaped nuclei are about 2 m thick and 7.6 m in diameter and are situated near the border of the cells. The cells are piled up to hexagonal columns. Their margin is serrate and where it reaches the boundary of the column, it has a thickness of about 0.34 m. Close to the boundaries of the columns, the cells are linked to their neighbours within the column and of the adjoining column by desmosomes. This layer of the epidermis is confined to those regions of the body surface which also contain electroreceptors.The other layers of the epidermis have a structure as usual in fish, except for the lack of goblet cells.

     

In vitro clonal propagation of tea (Camellia sinensis (L.) O. Kuntze)

A system for in vitro clonal propagation has been developed in tea plants. Shoots obtained from primary explants were induced from terminal buds and axillary buds of mature field-grown plants. Cultures were initiated from both types of explants on Murashige and Skoog (MS) medium supplemented with 10% coconut milk (CM), 200 mg l^-1 of yeast extract (YE), 1.4 M indoleacetic acid (IAA) and 17.8 M benzyladenine (BA). The shoot tips were multiplied on 1/2 strength MS medium containing 10% CM, 2.9 M IAA and 17.8 M BA. The larger shoots were separated after multiplication and rooted on 1/2 MS medium supplemented with 11.4 M ascorbic acid and 34.5 M indolebutyric acid (IBA). A pretreatment of the plants with an aqueous solution of 493 M IBA greatly increased the frequency of rooting. More than 60% of the rooted plants have been transferred to soil successfully.Abbreviations BA benzyladenine - IAA indoleacetic acid - IBA indolebutyric acid - YE yeast extract - CM coconut milk - MS Murashige and Skoog medium (1962)     

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