Genetic mapping between Gli-B1 locus and a telomeric C-heterochromatin band in wheat

Summary Using C-banding it has been possible to prove that the bread wheat varieties Holdfast and CapelleDesprez shows an intense band of telomeric heterochromatin on the short arm of chromosome 1B, while the variety Pané-247 presents a very thin band. Gliadin study using pH-acid electrophoresis revealed the existence of differences in the Gli-B1 locus in the three varieties. Analysis of the progeny of the (P x H) x CD hybrid revealed recombination between the heterochromatin C-band and locus Gli-B1, and allowed the genetic distance between the two markers to be calculated as 6.55±3.16 cMorgan. This is the first time the genetic distance from a locus to the chromosome telomere has been directly obtained in wheat. The heterochromatin C-band studied here gives us a cytological marker on chromosome 1B that can be used as a reference point in the localization of other genes.     

Der Feinbau des Auges der Mehlmotte,Ephestia kuehniella Zeller (Lepidoptera,Pyralididae)

Zusammenfassung Die Retinula im Ommatidium der Mehlmotte besteht aus einer wechselnden Anzahl (9–12, meist 11) langgestreckter, prismatischer Sinneszellen. Außerdem enthält jede Retinula nahe der Basalmembran im Zentrum zwischen diesen distalen Retinulazellen noch eine basale Retinulazelle. Die Längsachse der Retinula wird von der Achsenstruktur eingenommen, die aus Mikrovilli besteht. Ihr distaler Teil ist der Achsenfaden, der breitere, proximale Teil bildet das Rhabdom. Dieses erscheint im Querschnitt meist vierstrahlig gelappt, da seine Außenseite in Längsrichtung tief gekehlt ist. Der Rhabdomquerschnitt gliedert sich in mehrere Schöpfe parallel angeordneter Mikrovilli (Rhabdomsektoren); jeder Rhabdomsektor besteht aus 1 oder 2 Rhabdomeren. Die basale Retinulazelle entsendet einen kleinen Schopf von Mikrovilli in die proximale Spitze des Rhabdoms. Die distalen Retinulazellen setzen sich proximal in Neuriten fort, welche sich in Einkehlungen der basalen Retinulazelle bzw. der Tracheenendzelle einschmiegen. Jeweils eine Tracheole durchbricht zusammen mit dem Neuritenstrang einer Retinula die Basalmembran; sie verzweigt sich distal zu ca. 30 Tracheolen, die die Retinula umhüllen.Die Kristallkegelzellen grenzen distal an die Cornea; proximal laufen die Kristallkegelzellen eines Ommatidiums in einen gemeinsamen Fortsatz aus, der zwischen den Retinulazellen unmittelbar am Achsenfaden endet. — Nur das helladaptierte Auge wurde untersucht. Hierbei erscheint im distalen Teil der Retinula nur der Achsenfaden lichtdurchlässig, das Cytoplasma der Retinulazellen hingegen von Pigmentgrana durchsetzt und für Licht undurchlässig.

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Fine structure of the eye of the meal moth, Ephestia kuehniella Zeller (Lepidoptera, Pyralididae)

Summary In each ommatidium of the meal moth a retinula is formed from a varying number (9–12, mostly 11) of elongated, prismatic sense cells. In addition, a basal retinular cell is situated near the basement membrane in the center of the other (distal) retinular cells. The axis of the retinula is occupied by many microvilli forming the axial structure, the distal section of which is the slender axial thread. Proximally, the axial structure widens (to 8.5 m instead of 1 m in diameter) and is now called rhabdom. Cross sections of the rhabdom mostly look like a petaloid with four petals; this figure is due to longitudinal infoldings along the length of the rhabdom surface. The rhabdom cross section is subdivided into several brushes of microvilli (rhabdom sectors), each one being characterized by an approximately parallel arrangement of its microvilli. One rhabdom sector may be composed of one or two rhabdomeres respectively.The basal retinular cell participates in rhabdom formation through a small brush of microvilli at the proximal end of the rhabdom. Proximally, the distal retinular cells taper into slender neurites which are embedded in grooves at the surface of the basal retinular cell and the tracheal end cell respectively. One tracheole piercing the basement membrane together with the neurites of one retinula branches into about 30 tracheoles surrounding the retinula.The crystalline cone cells touch the cornea; proximally, their cytoplasm forms a point which eventually terminates amongst the distal tips of the retinular cells, immediately at the axial thread.—Our work was restricted to light adapted eyes; in this condition, light transmission in the distal part of the retinula seems to be blocked by retinular cell pigment except inside the axial thread.

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

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     

Variability in the 11S globulin fraction of seed storage proteins ofHelianthus (Asteraceae)

The seed storage globulins from sixHelianthus and four hybrids were studied using mono and bidimensional gel SDS electrophoresis (+ 2 mercaptoethanol). The polypeptide composition of each subunit was determined. Different pairs are specifically expressed according to the species studied. Three typical patterns were discriminated. All the studied species exhibit five subunits: two of them are expressed in all the species (₁₁ and ₂₂). The subunit corresponding to the ₁₁ pair is present inH. petiolaris and in the three populations ofH. annuus studied. The _2b2 pair is common toH. annuus andH. argophyllus. H. petiolaris presents two specific _2a2 and ₄₄ pairs andH. annuus a specific ₃₃ pair. InH. argophyllus _{11 33} or ₄₄ are never observed but are replaced by ₁₃ and ₃₁ pairs. Some globulins, poorly represented, are of forms but present chains of higher molecular weights (in the range 54–56 kDa). Expressing variations in the banding patterns between these species by the use of a similarity index reveals complete identity between the three populations ofH. annuus. Identity between the twoH. petiolaris studied is also observed.H. annuus andH. argophyllus appear to be closer to each other thanH. petiolaris concerning the seed storage globulins.     

Ibf-1 (Iodine binding factor), a highly variable marker system in the Triticeae

Summary Isoelectric focusing of extracts from the endosperm of mature grains of hexaploid wheat and related species was used to study the genetic control of Iodine binding factor (IBF). Ten IBF bands were present in Chinese Spring (CS) and analysis of the nullisomictetrasomic and ditelosomic lines of CS showed nine of them to be controlled by genes on the long arms of the homoeologous group 5 chromosomes. Five alleles were detected at Ibf-A1 locus, four at Ibf-B1 and four at Ibf-D1 among a sample of 46 wheat genotypes. Homoeoloci were found on chromosome 5R of Secale cereale, 5E of Agropyron elongatum, 5U of Aegilops umbellulata, 5Agⁱ of Agropyron intermedium, 5S¹ and 4S¹ of Aegilops sharonensis and 4H of Hordeum vulgare.     

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     

Purification and characterization of aspartate aminotransferase from developing embryos of the camel tick Hyalomma dromedarii

Aspartate transaminase (AST) activity in the camel tick Hyalomma dromedarii was followed throughout embryogenesis. During purification of AST to homogeneity, ion exchange chromatography lead to four separate forms (termed I, II, III and IV). AST II with the highest specific activity was pure after chromatography on Sephacryl S-300. The molecular mass of AST II was 52KDa for the native enzyme, composed of one subunit of 50KDa. AST II had a Km value of 0.67mM for -ketoglutarate and 15.1mM for aspartate. AST II had a pH optimum of 7.5 with heat stability up to 50°C for 15min. The enzyme was activated by MnCl₂, and inhibited by CaCl₂, MgCl₂, NiCl₂, and ZnCl₂.     

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.     

Benzyl-N-acetyl-α-d-galactosaminide inhibits the sialylation and the secretion of mucins by a mucin secreting HT-29 cell subpopulation

We have analysed the mucins synthesized by the HT-29 MTX cell subpopulation, derived from the HT-29 human colon carcinoma cells through a selective pressure with methotrexate (Lesuffleuret al., 1990,Cancer Res 50: 6334–43), in the presence of benzyl-N-acetyl--galactosaminide (GalNAc-O-benzyl), which is a potential competitive inhibitor of the 1,3-galactosyltransferase that synthesizes the T-antigen. The main observation was a 13-fold decrease in the sialic acid content of mucins after 24 h of exposure to 5mm GalNAc-O-benzyl. This effect was accompanied by an increased reactivity of these mucins to peanut lectin, testifying to the higher amount of T-antigen. The second observation was a decrease in the secretion of the mucins by GalNAc-O-benzyl treated cells. The decrease in mucin sialyation was achieved through thein situ -galactosylation of GalNAc-O-benzyl into Gal1–3GalNAc-O-benzyl, which acts as a competitive substrate of Gal1–3GalNAc 2,3-sialyltransferase, as shown by the intracellular accumulation of NeuAc2–3Gal1–3GalNAc-O-benzyl in treated cells.Abbreviations BSM bovine submaxillary mucin - MTX methotrexate - PBS sodium phosphate 10mm, NaCl 0.15m, pH 7.4 buffer - pNp p-nitrophenol - TBS Tris/HCl 10mm, NaCl 0.15m, pH 7.4 buffer Enzymes: CMP-NeuAc: Gal1–3/4GlcNAc 2,3-sialyltransferase, ST3(N), EC 2.4.99.6; CMP-NeuAc: Gal1–4GlcNAc 2,6-sialyltransferase, ST6(N), EC 2.4.99.1; CMP-NeuAc: Gal1–3GalNAc 2,3-sialyltransferase, ST3(O), EC 2.4.99.4; CMP-NeuAc: R-GalNAc1-O-Ser 2,6-sialyltransferase, ST6(O)-I, EC 2.4.99.3; CMP-NeuAc: NeuAc2–3Gal1–3GalNAc 2,6-sialyltransferase, ST6(O)-II, EC 2.4.99.7; UDP-GlcNAc: Gal1–3GalNAc-R·(GlcNAc to GalNAc) 1,6-N-acetylglucosaminyltransferase, EC 2.4.1.102; UDP-GlcNAc: GalNAc-R 1,3-N-acetylglucosaminyltransferase, EC 2.4.1.147; UDP-Gal: GalNAc-R 1,3-galactosyltransferase, EC 2.4.1.122.     

2-Hydroxyglutaryl-CoA dehydratase from Fusobacterium nucleatum (subsp. nucleatum): an iron-sulfur flavoprotein

Anaerobically prepared cell-free extracts from Fusobacterium nucleatum contain 2-hydroxyglutaryl-CoA dehydratase with a specific activity of 20 nkat mg^-1. The enzyme was purified 24-fold to a specific activity of 480 nkat mg^-1 by anion exchange chromatography, gel filtration and chromatography on Blue-Sepharose. The activity of the purified enzyme was strictly dependent on the reductant Ti(III)citrate and stimulated 25-fold by 0.15 mM ATP and 5 mM MgCl₂. ATP is hydrolysed to ADP during incubation with 2-hydroxyglutaryl-CoA dehydratase in the presence or absence of the substrate. The enzyme is extremely sensitive towards oxygen and is inhibited by 10 M chloramphenicol, 10 M 2,4-dinitrophenol or 0.15 mM hydroxylamine. The pure enzyme consists of three subunits (49 kDa), (39 kDa) and (24 kDa) in approximately equal amounts. In this respect the enzyme differs from the related 2-hydroxy-glutaryl-CoA dehydratase from Acidaminococcus fermentans and lactyl-CoA dehydratase from Clostridium propionicum both of which are composed of only two subunits with sizes comparable to those of and but require an additional protein for activity. The relative molecular mass of the native enzyme of about 100 kDa suggests a trimeric -structure. The homogeneous enzyme contains riboflavin (0.5 mol/112 kDa), iron and sulfur (3.5 mol/112 kDa each). Polyclonal antibodies directed against the 2-hydroxyglutaryl-CoA dehydratase from A. fermentans did not crossreact with cell free extracts or purified dehydratase from F. nucleatum. A comparison of the N-terminal amino acid sequences of the dehydratase subunits from A. fermentans and F. nucleatum, however, showed some similarities in the -subunits.Non-standard abbreviations DTT dithiothreitol - PAGE polyaccrylamide gel electrophoresis - VIS visible     

Cajaflavanone and cajanone released from Cajanus cajan (L. Millsp.) roots induce nod genes of Bradyrhizobium sp.

A broad-host-range plasmid (pEA2-21) containing a Bradyrhizobium sp (F-4) nod DABC-lacZ translation fusion was constructed and used to monitor nod gene expression in response to pigeonpea root exudate. Two nod-inducing compounds were isolated and identified. Spectral analysis using ultraviolet absorption, infrared spectra, proton nuclear magnetic resonance, and mass spectrometry showed that the two inducers were 5,4-dihydroxy-6-(3-methyl-2-butenyl)-2, 2-dimethyl pyrano-[5, 6:7, 8]-flavanone (cajaflavanone) and 2,4,5-trihydroxy-5-isopentenyl-6, 7-dimethylchromene iso-flavanone (cajanone). When pEA2-21 was introduced into Rhizobium trifolii and R. meliloti cajanone and cajaflavanone did not induce nod gene indicating that specificity of induction appears to be influenced by the host-strain genome.     

Die Homologie des Perigons der Zingiberaceen Ein Beitrag zur Morphologie und Phylogenie des Monokotylen-Perigons

Nicolaia elatior is used as an example to demonstrate that the mucronate tepals ofZingiberaceae correspond to hypsophylls (bracts) consisting of a leaf sheath and a rudimentary Oberblatt (= leaf petiole + lamina) represented by the mucro. Evidence for this interpretation is furnished by all available criteria: leaf sequence (exhibiting a complete continuum of forms from foliage leaves over cata- and hypsophylls to the tepals), nervature, and ontogeny.The present conception is compared with the well-founded thesis ofLeinfellner that the perigone ofLiliaceae is derived from the androecium. The different morphological status of the perigone in both families is not regarded as the result of different phylogenetic origin, but as a manifestation of morphogenetic transgressions from one phyllome category to an adjacent one: In theLiliaceae the perigone is under a strong morphogenetic influence of the androecium, and therefore displays staminal characters, in theZingiberaceae it is under the dominating influence of the extrafloral region, and thus appears as a hypsophyllous structure. If this assumption of a morphologically oscillating perigone is correct, it will be fundamentally impossible to demonstrate unequivocally the phylogenetic origin of the monocotyledonous perigone.

Im wissenschaftlichen Werk Prof. Dr.Walter Leinfellners steht an erster Stelle die Morphologie der Blütenorgane. Als sein dankbarer Schüler möchte ich ihm aus Anlaß seines 70. Geburtstages die folgende Studie zu einem Thema zueignen, das ihn wie mich gleichermaßen angesprochen hat und schon Gegenstand der Forschungsarbeit des Jubilars war: die Homologie des Monokotylen-Perigons.     

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.     

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.     

Production of a novel syrup containing neofructo-oligosaccharides by the cells of Penicillium citrinum

A novel syrup containing neofructo-oligosaccharides was produced from sucrose (Brix 70) by whole cells of Penicillium citrinum. The efficiency of fructo-oligosaccharides production was more than 55% and those of the main carbohydrate components, 1-kestose (Fruf 21Fruf 21 Glc), nystose (Fruf 21Fruf 21 Fruf 21 Glc) and neokestose (Fruf 26 Glc12 Fruf), were 22, 14 and 11%, respectively.     

Synthetic substrate analogues for UDP-GlcNAc: Manα1-6R β(1-2)-N-acetylglucosaminyltransferase II. Substrate specificity and inhibitors for the enzyme

UDP-GlcNAc: Man1-6R (1-2)-N-acetylglucosaminyltransferase II (GlcNAc-T II; EC 2.4.1.143) is a key enzyme in the synthesis of complexN-glycans. We have tested a series of synthetic analogues of the substrate Man1-6(GlcNAc1-2Man1-3)Man-O-octyl as substrates and inhibitors for rat liver GlcNAc-T II. The enzyme attachesN-acetylglucosamine in 1-2 linkage to the 2-OH of the Man1-6 residue. The 2-deoxy analogue is a competitive inhibitor (K _i=0.13mm). The 2-O-methyl compound does not bind to the enzyme presumably due to steric hindrance. The 3-, 4- and 6-OH groups are not essential for binding or catalysis since the 3-, 4- and 6-deoxy and -O-methyl derivatives are all good substrates. Increasing the size of the substituent at the 3-position to pentyl and substituted pentyl groups causes competitive inhibition (K _i=1.0–2.5mm). We have taken advantage of this effect to synthesize two potentially irreversible GlcNAc-T II inhibitors containing a photolabile 3-O-(4,4-azo)pentyl group and a 3-O-(5-iodoacetamido)pentyl group respectively. The data indicate that none of the hydroxyls of the Man1-6 residue are essential for binding although the 2- and 3-OH face the catalytic site of the enzyme. The 4-OH group of the Man-O-octyl residue is not essential for binding or catalysis since the 4-deoxy derivative is a good substrate; the 4-O-methyl derivative does not bind. This contrasts with GlcNAc-T I which cannot bind to the 4-deoxy-Man- substrate analogue. The data are compatible with our previous observations that a bisectingN-acetylglucosamine at the 4-OH position prevents both GlcNAc-T I and GlcNAc-T II catalysis. However, in the case of GlcNAc-T II, the bisectingN-acetylglucosamine prevents binding due to steric hindrance rather than to removal of an essential OH group. The 3-OH of the Man1-3 is an essential group for GlcNAc-T II since the 3-deoxy derivative does not bind to the enzyme. The trisaccharide GlcNAc1-2Man1-3Man-O-octyl is a good inhibitor (K _i=0.9mm). The above data together with previous studies indicate that binding of the GlcNAc1-2Man1-3Man- arm of the branched substrate to the enzyme is essential for catalysis. Abbreviations: GlcNAc-T I, UDP-GlcNAc:Man1-3R (1-2)-N-acetylglucosaminyltransferase I (EC 2.4.1.101); GlcNAc-T II, UDP-GlcNAc:Man1-6R (1-2)-N-acetylglucosaminyltransferase II (EC 2.4.1.143); MES, 2-(N-morpholino)ethane sulfonic acid monohydrate.     

The relation of proton motive force,adenylate energy charge and phosphorylation potential to the specific growth rate and efficiency of energy transduction inBacillus licheniformis under aerobic growth conditions

The magnitude of the proton motive force (p) and its constituents, the electrical () and chemical potential (-ZpH), were established for chemostat cultures of a protease-producing, relaxed (rel ^–) variant and a not protease-producing, stringent (rel ⁺) variant of an industrial strain ofBacillus licheniformis (respectively referred to as the A- and the B-type). For both types, an inverse relation of p with the specific growth rate was found. The calculated intracellular pH (pH_in) was not constant but inversely related to . This change in pH_in might be related to regulatory functions of metabolism but a regulatory role for pH_in itself could not be envisaged. Measurement of the adenylate energy charge (EC) showed a direct relation with for glucose-limited chemostat cultures; in nitrogen-limited chemostat cultures, the EC showed an approximately constant value at low and an increased value at higher . For both limitations, the ATP/ADP ratio was directly related to .The phosphorylation potential (G'p) was invariant with . From the values for G'p and p, a variable H⁺/ATP-stoichiometry was inferred: H⁺/ATP=1.83+0.52µ, so that at a given H⁺/O-ratio of four (4), the apparent P/O-ratio (inferred from regression analysis) showed a decline of 2.16 to 1.87 for =0 to _max (we discuss how more than half of this decline will be independent of any change in internal cell-volume). We propose that the constancy of G'p and the decrease in the efficiency of energy-conservation (P/O-value) with increasing are a way in which the cells try to cope with an apparent less than perfect coordination between anabolism and catabolism to keep up the highest possible with a minimum loss of growth-efficiency. Protease production in nitrogen-limited cultures as compared to glucose-limited cultures, and the difference between the A- and B-type, could not be explained by a different energy-status of the cells.Abbreviations CCCP carbonylcyanide-p-trichloromethoxyphenylhydrazone - DW dry weight of biomass - F Faraday's constant, 96.6 J/(mV × mol) - Fo chemostat outflow-rate (ml/h) - FCCP carbonylcyanide-p-trifluoromethoxyphenylhydrazone - G'p phosphorylation potential, the Gibbs energy change for ATP-synthesis from ADP and P_i - G'⁰p standard Gibbs energy change at specified conditions - H⁺/ATP number of protons translocated through - ATP synthase in synthesis of one ATP - H⁺/O protons translocated during transfer of 2 electrons from substrate to oxygen - specific growth rate (1/h) - _H+ transmembrane electrochemical proton potential, J/mol - M_b molar weight (147.6 g/mol) of bacteria with general cell formula C_6.0H_10.8O_3.0N_1.2 - pH_out,in extracellular, intracellular pH - P_i (intracellular) inorganic phosphate - p proton motive force, mV - pH transmembrane pH-difference - transmembrane electrical potential, mV - P/O number of ADP phosphorylated to ATP upon reduction of one O^2– to H₂O by two electrons transferred through the electron transfer chain - P/O (H⁺/O) × (H⁺/ATP)^–1 - P/O_F, P/O_N P/O with the two electrons donated by resp. (NADH + H⁺) and FADH - q specific rate of consumption or production (mol/g DW × h) - rel ⁺,rel ^– stringent, relaxed genotype - R universal gas constant, 8.36 J/(mol × degree) - T absolute temperature - TPMP⁺ triphenylmethylphosphonium ion - TPP⁺ tetraphenyl phosphonium ion - Y growth yield, g DW/mol - Z conversion constant=61.8 mV for 310 K (37 °C) - ZpH transmembrane proton potential or chemical potential, mV     

Endogenous abscisic acid and 2-trans-abscisic acid in alternate bearing ‘Wilking’ mandarin trees

The relationship of abscisic acid (ABA) and 2-trans-abscisic acid (t-ABA) to alternate bearing has been examined in Wilking mandarin (Citrus reticulata Blanco) trees. Leaves, stems and buds of trees loaded with fruit (on trees) had 4.3, 6.0 and 2.2 fold higher ABA levels than the corresponding organs from off trees. Leaves had higher ABA levels than stems and buds in both on and off trees. t-ABA was non-detectable in Wilking leaf, stem and bud tissue. Amounts of t-ABA not exceeding 40% of the ABA content, were found in Shamouti and Valencia orange buds and in Wilking fruit peel.The elevated levels of ABA in on tree organs may reflect a stress imposed by the fruit overload.     

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.