Carotenoid pigments of Sorangium compositum (Myxobacterales) including two new carotenoid glucoside esters and two new carotenoid rhamnosides

Summary The carotenoid pigments of the myxobacterium Sorangium compositum were analyzed by chromatographical and chemical techniques and by visible, infra red, and mass spectroscopy. Besides -carotene, neurosporene, torulene, lycopene, and 1,2-dihydro-1-hydroxy--carotene, four new carotenoid glycosides were found. These pigments were identified as 1,2-dihydro-1-hydroxy-torulene glucoside ester (I), 1,2-dihydro-3,1-dihydroxy-torulene glucoside ester (III), 1,2-dihydro-1-hydroxy-torulene rhamnoside (II), and 1,2-dihydro-3,1-dihydroxytorulene rhamnoside (IV).Fifth communication on the carotenoids of myxobacteria. Fourth communication see Arch. Mikrobiol. 76, 364–380 (1971).     

The meaning of interaction parameters in two-state protein complexes

The theory of interaction parameters has thus far been based on the free-energy relationships in the formation of ternary complexes formed between a pair of ligands and a protein molecule. The concept has been formulted in terms of a thermodynamic square comprised of the free protein, the two binary complexes, and the ternary complex. However, an increasing number of proteins have been found to exist as equilibrium mixtures of two macrostates. The equilibrium constants for such two-state transitions vary quite considerably between the various binary and ternary complexes of a given protein. We show here that the interpretations of interaction parameters in such two-state systems, requiring the use of a thermodynamic cube, are much more complex than those based on the classic thermodynamic square commonly employed. We demonstrate the use of enthalpies of interaction and heat capacities of interaction to analyze the source of observed free enerigies of interaction in such systems. Specifically, we find that measured negative interaction parameters may arise simply from the inability of a system to achieve all of the positive component effects anticipated by the conventional formulation.     

Protonmotive force driven 6-deoxyglucose uptake by the oral pathogen,Streptococcus mutans Ingbritt

Streptococcus mutans Ingbritt was grown in glucose-excess continuous culture to repress the glucose phosphoenolpyruvate phosphotransferase system (PTS) and allow investigation of the alternative glucose process using the non-PTS substrate, (³H) 6-deoxyglucose. After correcting for non-specific adsorption to inactivated cells, the radiolabelled glucose analogue was found to be concentrated approximately 4.3-fold intracellularly by bacteria incubated in 100 mM Tris-citrate buffer, pH 7.0. Mercaptoethanol or KCl enhanced 6-deoxyglucose uptake, enabling it to be concentrated internally by at least 8-fold, but NaCl was inhibitory to its transport. Initial uptake was antagonised by glucose but not 2-deoxyglucose. Evidence that 6-deoxyglucose transport was driven by protonmotive force (p) was obtained by inhibiting its uptake with the protonophores, 2,4-dinitrophenol, carbonylcyanide m-chlorophenylhydrazine, gramicidin and nigericin, and the electrical potential difference () dissipator, KSCN. The membrane ATPase inhibitor, N,N¹-dicyclohexyl carbodiimide, also reduced 6-deoxyglucose uptake as did 100 mM lactate. In combination, these two inhibitors completely abolished 6-deoxyglucose transport. This suggests that the driving force for 6-deoxyglucose uptake is electrogenic, involving both the transmembrane pH gradient (pH) and . ATP hydrolysis, catalysed by the ATPase, and lactate excretion might be important contributors to pH.Abbreviations DNP 2,4-dinitrophenol - CCCP carbonylcyanide m-chlorophenylhydrazone - DCCD N,N¹-dicyclohyxyl carbodiimide - p protonmotive force - pH transmembrane pH gradient - transmembrane electrical potential difference     

Cryptomonad biliproteins — an evolutionary perspective

Each cryptomonad strain contains only a single spectroscopic type of biliprotein. These biliproteins are isolated as 50000 kDa '₂ complexes which carry one bilin on the and three on the subunit. Six different bilins are present on the cryptomonad biliproteins, two of which (phycocyanobilin and phycoerythrobilin) also occur in cyanobacterial and rhodophytan biliproteins, while four are known only in the cryptomonads. The subunit is encoded on the chloroplast genome, whereas the subunits are encoded by a small nuclear multigene family. The subunits of all cryptomonad biliproteins, regardless of spectroscopic type, have highly conserved amino acid sequences, which show > 80% identity with those of rhodophytan phycoerythrin subunits. In contrast, cyanobacteria and red algal chloroplasts each contain several spectroscopically distinct biliproteins organized into macromolecular complexes (phycobilisomes). The data on biliproteins, as well as several other lines of evidence, indicate that the cryptomonad biliprotein antenna system is primitive and antedates that of the cyanobacteria. It is proposed that the gene encoding the cryptomonad biliprotein subunit is the ancestral gene of the gene family encoding cyanobacterial and rhodophytan biliprotein and subunits.Abbreviations Chl chlorophyll - CER chloroplast endoplasmic reticulum - SSU rRNA small subunit ribosomal RNA     

An elongated segment of DNA observed between two human α globin genes

Summary Detailed restriction enzyme analysis of the DNA from a Chinese female showed that one of her chromosomes had a >17.5 kb deletion of DNA, including the , 2, and 1 globin genes, which is present in many Southeast Asians with an -thalassemia-1 chromosome. Her normal chromosome had the expected cluster of -like globin genes (5----2-1-3), but the segment of DNA between the two globin genes was elongated by some 0.5–0.7 kb. Analyses of various restriction sites suggested that this normal variant of the human globin gene complex is due to a crossover between a normal chromosome with () and a chromosome with an -thalassemia-2 (–^3.7) and an -21-hybrid gene.     

Organogenesis from ‘Passe Crassane’ and ‘Old Home’ pear (Pyrus communis L.) protoplasts and isoenzymatic trueness-to-type of the regenerated plants

Summary Large numbers of highly viable mesophyll protoplasts were isolated from shoot cultures of the scion cv Passe Crassane and the rootstock genotype Old Home of common pear (Pyrus communis L.). Protoplasts were cultured for both genotypes either as liquid layers or as liquid-over-agar cultures, in ammonium-free MS medium with 0.5 M mannitol, 50 mg/l casein enzymatic hydrolysate (CEH), 2.0 mg/l NAA and 1.0 mg/l BAP, plus either 0.5 mg/l IAA (for Old Home) or 2.0 mg/l IAA (for Passe Crassane). Protoplast microcalli, obtained by day 60 (Passe Crassane) or day 80 (Old Home), were transferred for further growth to ammonium-free MS medium with 2.0 mg/l NAA and 1.0 mg/l BAP. Shoot bud regeneration from the protoplastderived callus was first attempted between 100 (Passe Crassane) and 120 (Old Home) days after protoplast isolation. For Passe Crassane, shoot buds were regenerated (day 130) on a half-strength MS medium with 0.1 mg/l IBA, 0.5 mg/l BAP, 50 mg/l CEH and 20 mg/l Ca-panthotenate. For Old Home, shoot but regeneration only occurred 30 days later and on the same medium as above, which was additionally supplemented with double the concentration of the group B vitamins found in the original MS formulation and 0.05 mg/l GA₃. Following micropropagation and in vitro rooting of shoots, the plants were transferred to soil following standard procedures. Trueness-to-type of the regenerated plants was assessed by analysing their leaf isozyme banding profiles (for EST, AP, PRX, SOD, ENP, LAP, PGI, AAT, ADH, MDH and PGM) and comparing them to those corresponding to the original shoots that provided the protoplasts. No differences between the mother shoots and the protoclones were observed for any one of the 11 isozyme systems studied.     

Phylogeny of immunoglobulin heavy chain isotypes: structure of the constant region of Ambystoma mexicanum υ chain deduced from cDNA sequence

An RNA polymerase chain reaction strategy was used to amplify and clone a cDNA segment encoding for the complete constant part of the axolotl IgY heavy (C) chain. C is 433 amino acids long and organized into four domains (C1–C4); each has the typical internal disulfide bond and invariant tryptophane residues. Axolotl C is most closely related to Xenopus C (40% identical amino acid residues) and C1 shares 46.4% amino acid residues among these species. The presence of additional cysteines in C1 and C2 domains is consistent with an additional intra-domain S-S bond similar to that suggested for Xenopus C and C, and for the avian C and the human C. C4 ends with the Gly-Lys dipeptide characteristic of secreted mammalian C3, human C4, and avian and anuran C4, and contains the consensus [G/GT(AA)] nucleotide splice signal sequence for joining C4 to the transmembrane region. These results are consistent with the hypothesis of an ancestral structural relationship between amphibian, avian chains, and mammalian chains. However, these molecules have different biological properties: axolotl IgY is secretory Ig, anuran and avian IgY behave like mammalian IgG, and mammalian IgE is implicated in anaphylactic reactions.The nucleotide sequence data reported in this paper have been submitted to the EMBL/GenBank nucleotide sequence database and have been assigned the accession number X69492. Correspondence to: J. S. Fellah.     

Nucleic acid metabolism in yeast

Summary The three haploid yeast strains T2tmp1-3, T2tmp1-1, and T6tmp1-51 auxotrophic for 5-dTMP differ in their requirement for thymidylate: 72, 16, and 3 g 5-dTMP/ml will restore optimal growth, respectively. Thymidylate low requirement in strain T2tmp1-1 and T6tmp1-51 is termed tlrA and tlrC, respectively. When the growth medium is made 5x10^-4 M for 5-dTMP only strain T6tmp1-51 is severely inhibited in RNA and DNA synthesis. This inhibition is reversible after removal of excessive 5-dTMP. The inhibitory characteristic is in marked contrast to thymineless death due to the lack of 5-dTMP in strain T6tmp1-51 where only DNA synthesis stops while RNA synthesis continues. The inhibitory effect of 5x10^-4 M 5-dTMP is not due to the 5-dTMP auxotrophy but to the thymidylate low requiring character (tlrC) in strain T6tmp1-51. The arrest of RNA and DNA synthesis by high concentrations of exogenous 5-dTMP suggests a regulatory role of either the monoor triphosphate on nucleoside or nucleotide biosynthesis in yeast.     

A new enzymatic route to the synthesis of 12-ketoursodeoxycholic acid

Summary Cholic acid (3,7,12-trihydroxy-5-cholanoic acid) was completely and selectively transformed into 12-ketoursodeoxycholic acid (3,7-dihydroxy-12-oxo-5-cholanoic acid) by means of two consecutive enzymatic steps catalyzed, the first, by 7- and 12-hydroxysteroid dehydrogenase and, the second, by 7-hydroxysteroid dehydrogenase. Coenzyme regeneration was carried out with -ketoglutarate-glutamate dehydrogenase and glucose-glucose dehydrogenase, respectively.     

Cleavage of nucleotides by Ce4+ and the lanthanide metal complexes

The cleavage of adenosine-5-monophosphate (5-AMP) and guanosine-5-monophosphate (5-GMP) by Ce⁴⁺ and lanthanide complex of 2-carboxyethylgermanium sesquioxide (Ge-132) in acidic and near neutral conditions was investigated by NMR , HPLC and measuring the liberated inorganic phosphate at 37°C and 50°C. The results showed that 5-GMP and 5-AMP was converted to guanine (G), 5-monophosphate (depurination of 5-GMP), ribose (depurination and dephosphorylation of 5-GMP), phosphate and adenine (A), 5-monophosphate (depurination of 5-AMP), ribose (depurination and dephosphorylation of 5-AMP), phosphate respectively by Ce⁴⁺. In presence of lanthanide complexes, 5-GMP and 5-AMP were converted to guanosine (Guo) and phosphate and adenosine (Ado) and phosphate respectively. The mechanism of cleaving 5-GMP and 5-AMP is hydrolytic scission     

Analysis of the effect of rye chromosomes 4R, 6R and telomeric heterochromatin on 7R on homologous chromosome pairing in pentaploid hybrids (AABBR,AABBD)

Summary Meiotic pairing in Triticum turgidum cv. Ma (4x) with a mean chiasmata frequency of 27.16 per cell was compared with chiasmata frequencies in its hybrids with several triticale strains, Chinese Spring wheat and its addition lines for Imperial rye chromosomes 4R and 6R. In hybrids between Ma and x Triticosecale cv. Rosner the chiasmata frequency was marginally reduced by an average of 1.25%, by 8.8% in hybrids with x Triticosecale cv. DRIRA HH and by 6.7% with DRIRA EE (lacking 90% telomeric heterochromatin from chromosome arm 7RL). In pentaploid hybrids between Ma and T. aestivum cv. Chinese Spring the reduction was an average of 10.30%, while addition lines with rye chromosome 6R reduced chiasmata frequencies by an average of 7.4% and rye addition line for 4R showed the greatest depression in chiasmata frequency in hybrids by a 25.04% reduction. An interchange difference involving long chromosome segments was observed between Ma and Rosner.Contribution No. 819 Ottawa Research Station     

α-Amylase structural genes in rye

Summary Rye -Amy1, -Amy2, and -Amy3 genes were studied in the cross between inbred lines using wheat -amylase cDNA probes. The -Amy1 and -Amy2 probes uncovered considerable restriction fragment length polymorphism, whereas the -Amy3 region was much more conserved. The numbers of restriction fragments found and the F₂ segregation data suggest that there are three -Amy1 genes, two or three -Amy2 genes, and three -Amy3 genes in rye. These conclusions were supported by a simultaneous study of -amylase isozyme polymorphism. The F₂ data showed the three individual -Amy1 genes to span a distance of 3cM at the locus on chromosome 6RL. The genes were mapped relative to other RFLP markers on 6RL. On chromosome 7RL two -Amy2 genes were shown to be separated by 5 cM. Linkage data within -Amy3 on 5RL were not obtained since RFLP could be detected at only one of the genes.     

Donor tissue and culture condition effects on mesophyll protoplasts of Medicago sativa

Mesophyll protoplasts were produced from clones of two cultivars of Medicago sativa, Rangelander and Regen S. Protoplasts from the Regen S clone generally gave rise to calli while those from the Rangelander clone would undergo direct embryogenesis. Effects of plant growth conditions, donor tissue pretreatment and protoplast culture conditions on mesophyll protoplast production and subsequent development patterns were investigated. The major factor determining whether or not mesophyll protoplasts would be produced from either of the clones was the pretreatment in water of shoots excised from the donor plants. Pretreatment in water containing growth regulators did not alter protoplast production or development in the Regen S clone. Pretreatment of the Rangelander clone shoots with abscisic acid or naphthaleneacetic acid was slightly beneficial to embryo production while pretreatment with benzylaminopurine was detrimental. Altered leaf morphology induced by growth condition changes did not affect mesophyll protoplast production or subsequent development patterns when shoots were pretreated in water. Culture of protoplasts in liquid droplets or solid agar medium increased low density protoplast survival and subsequent embryo production in the Rangelander clone.     

Molecular evolution of the nicotinic acetylcholine receptor: An example of multigene family in excitable cells

An extensive phylogenetic analysis of the nicotinic-acetylcholine-receptor subunit gene family has been performed by cladistic and phenetic methods. The conserved parts of amino acid sequences have been analyzed by CLUSTAL V and PHYLIP software. The structure of the genes was also taken in consideration. The results show that a first gene duplication may have occurred before the appearance of Bilateria. Three subfamilies then appeared: I-the neuronal -bungarotoxin binding-site subunits (7, 8); III-the neuronal nicotinic subunits (2–6, 2–4), which also contain the muscle acetylcholine-binding subunit (1); and IV—the muscle non- subunits (1, , ). The Insecta subunits (subfamily II) could be orthologous to family III and IV. Several tissular switches of expression from neuron to muscle and the converse can be inferred from the extant expression of subunits and the reconstructed trees. The diversification of the neuronal nicotinic subfamily begins in the stem lineage of chordates, the last duplications occurring shortly before the onset of the mammalian lineage. Such evolution parallels the increase in complexity of the cholinergic systems.Abbreviations -Bgt -bungarotoxin - ACh acetylcholine - MP maximum of parsimony - MYA million years ago - NJ neighbor-joining - nAChR nicotinic acetylcholine receptor Correspondence to: N. Le Novère     

Long-term continuous reaction of immobilized β-fructofuranosidase

Summary -Fructofuranosidase was immobilized by alginate gel at high efficiency (92 %). The extreme long-term continuous reaction (half-life, 275 days) was achieved by the immobilized enzyme using sucrose at high concentration (500 mg ml^–1) to produce fructo-olicosaccharides, such as 1-kestose (Fru21Fru21aGlc) and nystose (Fru21Fru21Fru21aGlc).     

Ganglioside-cholera toxin interactions: a binding and lipid monolayer study

Summary On t.l.c. plates ¹²⁵I-cholera toxin binds to a disialoganglioside tentatively identified as GD_lb with about 10 times less capacity than to ganglioside GM₁. Binding of labeled toxin to both gangliosides was abolished in presence of excess amounts of unlabeled B subunit. Ganglioside extracts from human or pig intestinal mucosa showed toxin binding to gangliosides GM₁ and GD_1b. In ganglioside-containing lipid monolayers the penetration of the toxin was independent of the ganglioside binding capacity.Abbreviations GM₂ Gal-NAc14Gal(3-2NeuAc)14G1c1Cer - GM₁ Gal3Ga1-NAc14Gal(32NeuAc)14G1c11Cer - GD_1a NeuAc23Ga113Gal-NAc14Gal(32NeuAc)14G1c11Cer - GD1b Gall3Gal-NAcl4Gal(32NeuAc82NeuAc)14Glc11Cer - GT_1b NeuAc23Ga113Ga1-NAcal4Gal(3-2NeuAc82NeuAc)14G1c11Cer - dpPC 1,2-hexadecanoyl-sn-glycero-3-phosphocholine - dpPE 1,2-hexadecanoyl-sn-glycero-3-phosphoethanolamine     

Identification of a 4A/7R and a 7B/4R wheat-rye chromosome translocation

Summary By producing chromosome substitutions with Imperial rye chromosomes 4R (C) and 7R (D) in the wheat cultivar Chinese Spring two spontaneous translocation lines were obtained. One involves segments of wheat chromosome 4A and rye chromosome 7R, the other involves portions of wheat chromosome 7B and rye chromosome 4R     

Heterosis among populations of maize (Zea mays L.) with different levels of exotic germplasm

Summary Thirteen maize (Zea mays L.) populations including five adapted, five adapted x exotic, two composites of adapted and exotic, and one exotic selected for adaptability were crossed in a diallel mating system. The parents and 78 crosses and nine check hybrids were evaluated for grain yield and plant height in five environments. The Gardner-Eberhart model Analysis II indicated that additive and nonadditive gene effects accounted for 60 and 40% of the total variation among populations, respectively, for grain yield and 86% and 14% of the total variation, respectively, for plant height. Components of heterosis were significant in the combined analysis for both traits. Adapted Corn Belt populations tended to have higher performance in crosses and greater values of variety heterosis than 50% adapted populations. Nebraska Elite Composite, Corn Belt x Mexican, and Corn Belt x Brazilian showed high mean yields in crosses, however, they were not among those with high estimates of variety heterosis. One exotic population (Tuxpeno x Antigua Grupo 2) and three adapted populations [307 Composite, NB(S₁)C-3, and NK(S₁)C-3] might be combined together to form a high-yielding population. It may be possible to synthesize two useful populations for reciprocal recurrent selection by grouping Tuxpeno x Antiqua Grupo 2, NB(S₁)C-3, and NS(FS)LFW-8 into one population and NK(S₁)C-3, KrugxTabloncillo, and 307 Composite in the other one.Contribution from the Department of Agronomy, University of Nebraska, Lincoln, NE 68583. Published as Paper No. 8011. Journal Series, Nebr. Agric. Exp. Station. Research was conducted under Project 12-049     

Production of thermostable amylolytic enzymes by Thermococcus hydrothermalis

A cell extract of Thermococcus hydrothermalis, grown for 6 h, gave -glucosidase activity at 14.9 U/l, degrading oligosaccharides and maltose. -Amylase, -glucosidase and pullulanase activities were detected at 289 U/l, 13.5 U/l and 30 U/l respectively in the culture medium after 24 h growth of the archaeum. All of three enzymes, characterised by a half-life time of 1 to 5 h at 95°C, degraded both the (14) and (16) linkages of polysaccharides and the (14) linkages of oligosaccharides. © Rapid Science Ltd. 1998     

TNF alpha is required for hypoxia-mediated right ventricular hypertrophy

Hypoxia has been shown to activate the pleiotropic cytokine TNF in the lung. TNF in turn, is known to induce pulmonary vasoconstriction. Additional effects of this cytokine in hypoxia mediated cardiopulmonary remodeling are poorly understood. To further evaluate the role of TNF in chronic hypoxia we exposed TNF null (TNF–/–) and wild-type mice to three weeks of hypobaric hypoxia (10% O₂). Equivalent erythocytosis (Hematocrit increased by 40%) developed in both genetic backgrounds. In contrast, right ventricular systolic pressure increased in response to three weeks of hypoxia in the wild-type mice ( 75%), yet was unaltered in the TNF–/– mice. Concomitantly right ventricular hypertrophy was attenuated in the TNF–/– mice (35 ± 5% increase) when compared to wild-type mice (124 ± 6% increase p < 0.001, n 20). Interestingly in both strains the lung wet weights increased to a similar degree in response to hypoxia. In conclusion, our data demonstrate that TNF is an integral autocoid in chronic hypoxia mediated right ventricular hypertrophy. Moreover, additional components of cardiopulmonary remodeling may be regulated by TNF signaling as suggested by the negligible right ventricular systolic pressure response to hypoxia in the absence of TNF.