Genome Sequence of Idiomarina xiamenensis Type Strain 10-D-4

Idiomarina xiamenensis strain 10-D-4^T was isolated from an oil-degrading consortium enriched from surface seawater around the Xiamen island. Here, we present the draft genome of strain 10-D-4^T, which contains 2,899,282 bp with a G+C content of 49.48% and contains 2,673 protein-coding genes and 43 tRNA genes.     

Potassium influx and efflux of 2,4-D- and MCPA-treated rice plants

Summary A study was made of the effects of the herbicides 2,4-D (2,4-dichlorophenoxyacetic acid) and MCPA (4-chloro-2-methyl-phenoxyacetic acid) on ion uptake, leakage and growth of rice seedlings. Using isotopically-labelled solutions containing different concentrations of 2,4-D or MCPA, it was established that 10^–4 M 2,4-D or MCPA effectively inhibited potassium ion uptake, while K-ion leakage from the roots occurred only at 10^–3 M. The growth of the rice seedlings was markedly retarded even at low (10^–6 M) concentrations, and the roots and shoots showed different tolerances to the herbicide. At 10^–8 M herbicide, the effects were not injurious, but rather favourable. Reduction in root length by herbicides was not in accordance with dry-matter production.     

Enzymatic synthesis of β-D-2', 3'-unsaturated-5-fluorocytidine from β-D-2',3'-unsaturated thymidine

We have used crude preparations of N-deoxyribosyl transferases (NdRT-II) from Lactobacillus helveticus to catalyze the transfer of a glycosyl moiety from a donor nucleoside to an acceptor base. Optimal conditions for the transglycosylation reaction to make D-D4FC starting from D-D4T and 5-FC were determined after the analysis of several experimental parameters including reaction time, concentration of substrate, pH and the type of buffer. For the first time, a practical procedure for enzymatic synthesis of β-D-2',3'-unsaturated-5-fluorocytidine (β-D-2',3'-didehydro-2',3'-dideoxy-5-fluorocytidine, D-D4FC) from β-D-2',3'-unsaturated thymidine (D-D4T) has been established. This method will be useful in the manufacture of important nucleoside analogues for anti-viral therapy.     

Interaction of rat liver 3-D-(-)-hydroxybutyrate aopdehydrogenase with phospholipids

The interaction of phospholipids with pure, catalytically inactive rat liver 3-d-(—)-CoA hydroxybutyrate apodehydrogenase (apoHBD) was examined, (a) A relationship could be established between density of packing of phospholipid molecules at the interface and apoHBD activation, namely, the larger the area per polar head, the higher the lipid molar efficiency. In this context, codispersion of lecithins with phospholipids that were inactive or scarcely active per se, such as phosphatidylethanolamine and lysophosphatidylcholine (miristoyl; Iysod₁₄) increased the activating efficiency of lecithins, (b) ApoHBD formed tightly bound, catalytically active complexes with lecithin liposomes and micelles (diC₁₀ + lysoC₁₄; cetylphosphorylcholine), but a phospholipid-water interface was not essential for HBD activity since a molecular dispersion of diheptanoyl lecithin (diC₇) activated apoHBD to a limited extent. ApoHBD formed loosely bound, catalytically inactive complexes with multilayer vesicles, but HBD activity could be restored by sonication or by adding liposome to those complexes. Unlike liposomes and micelles, apoHBD interaction with multilayer vesicles did not involve a hydrophobic contribution, which was apparently necessary for apoHBD activation, (c) LysoC₁₄, did₁₀ + lysoC₁₄, and cetylphosphorylcholine micelles activated apoHBD but diC₇ micelles inhibited the HBD activity of the apoHBD-diC₇ (monomer) complex. The inhibition decreased when the medium ionic strength was increased. Liposomes and diCi₁₀ + lysoC₁₄ micelles activated and stabilized apoHBD much more efficiently than pure lysoC₁₄ or cetylphosphorylcholine micelles, (d) The mode of aggregation of the activating phospholipid strongly affected the kinetics of the HBD reaction. With liposomes the reaction showed an initial lag (or induction) period whose duration varied over a range of 3 to 15 min, depending on the activating phospholipid; with diC₇ monomers and micelles the kinetics was linear throughout, while with multilayer vesicles the lag was virtually infinite since HBD activity was insignificant, (e) Energies of activation for apoHBD-diC₁₄ complexes, either below or above the lecithin gel-to-liquid crystalline transition temperature were not significantly different, in accordance with apoHBD interaction with the proximal end of the hydrocarbon chains, that is, the less subject to phase transitions. With a diC₁₄-substituted mitochondrial preparation, however, no HBD activity was detected below 24 °C (near the gel-to-liquid crystalline transition temperature of diC₁₄), thus indicating that, in the inner membrane, apoHBD interacts with the whole length of the fatty acyl chain and, consequently, is sensitive to phase transition.     

Purification of apo-3-D-(-) hydroxybutyrate dehydrogenase from rat liver mitochondria

Summary 3-D-(-) hydroxybutyrate dehydrogenase (EC 1.1.1.30) from rat-liver mitochondria was purified in the form of the soluble, phospholipid-free apoenzyme by a procedure involving: (1) solubilization of the membrane bound enzyme by controlled digestion of membrane phospholipids with porcine pancreas phospholipase A₂; (2) stabilization and separation of the released apoenzyme as a complex with egg-lecithin by gel filtration on Sephadex G-100; and (3) specific displacement of the apoenzyme from the enzyme-lecithin complex by treatment withBothrops atrox venom phospholipase A₂ (in the absence of Ca²⁺ ions) and subsequent separation of the displaced apoenzyme by gel filtration on Sephadex G-100. The method described is adequate for samples containing about 40 mg of mitochondrial protein. The yield in activity is 42% of that present in mitochondria and the degree of purification of the apodehydrogenase is about 170 fold. The purified apodehydrogenase shows one single sharp band when submitted to SDS polyacrylamide gel electrophoresis, with a mobility corresponding to a molecular weight of 38000 daltons. Gel filtration of the apoenzyme on Sephadex G-100 shows two active peaks with molecular weights of 76000 and 38500 daltons, indicating two different states of aggregation, namely, monomer and dimer. The corresponding diffusion coefficients are 7.73 (monomer) and 5.70 (dimer) × 10^–7. The apodehydrogenase preparation is devoid of phospholipids and is catalytically inactive. It can be reactivated by addition of egg lecithin or phospholipid mixtures containing lecithin in a suitable physical state. Reactivation occurs after formation of an active apodehydrogenase phospholipid complex.Abbreviations HBD 3-D-(-) hydroxybutyrate dehydrogenase - apoHBD 3-D-(-) hydroxybutyrate dehydrogenase apoenzyme - SMP submitochondrial particles - DFP diisopropylfluorophosphate - BSA bovine serum albumin - MPL mitochondrial phospholipids - L-diC₁₄ 1,2-dimyristoyl-sn-glycero-3-phosphorylcholine - lysoC₁₄ 1-myristoyl-sn, glycero-3-phosphorylcholine - D-diC₁₀ 2.3-didecanoyl-sn-glycero-1-phosphorylcholine - tlc thin layer chromatography - SDS sodium dodecylsulfate Dedicated to ProfessorLuis F. Leloir on the occasion of his 70th birthday.     

Root georeaction affected by exo-{beta}-D-(l,3)-glucanase

Two hour pretreatment with exo-ß-D-(l,3)-glucanasecause (at a concentration of 0.4 unit/ml) significant stimulationof the georeaction of maize apical root segments, horizontallyplaced for 7 hr. Implications of this enzyme effect on cellwall extension are discussed. (Received September 8, 1975; )     

Conversion of 9-D- and 13-L-hydroperoxylinoleic acids by soybean lipoxygenase-1 under anaerobic conditions.

Soybean lipoxygenase-1 reacts with both 9-D and 13-L-hydroperoxylinoleic acids under anaerobic conditions. Approximately 40% of the hydroperoxide is converted into oxodienes, absorbing at 285 nm. Concomitantly, more polar compounds are formed, tentatively identified as being mainly epoxy-hydroxy-octadecenoic acids. When oxygen is present, the reaction is strongly inhibited, until in a very slow reaction the oxygen has been depleted. This accounts for the occurrence of a lag period.     

Conformational studies of linear β-D-1,4′-mannan and galactan

The nonbonded interaction energy of disaccharides, mannobiose and galactobiose and polysaccharides mannan and galactan have been computed as a function of dihedral angles (?,ψ). The conformation (40°, ?20°) has been preferred for the mannan chain from nonbonded interaction energy considerations. The O₅…O₃′ type of intramolecular hydrogen bond has been found to be possible in the above conformation. Comparison of the allowed region of mannan with those of cellulose and xylan indicates that the monomer unit, in mannan chain has slightly higher freedom of rotation than that of cellulose and less than that of xylan. As in cellulose and mannan, the freedom of rotation of the monomer units in β-1,4′ galactan is highly restricted. Unlike mannan (which prefers an extended conformation) the β-1,4′ galactan prefers a helical conformation similar to amylose. Just as in amylose the O₂…O₃′ type hydrogen bond between contiguous residues is also possible in β-1,4′ galactan.     

Sitosteryl-β-D-(6-O-fattyacyl)-glucopyranosides from the crude phosphatides of maize [1]

A new component of the crude phosphatides of Zea Mays Linn. has been identified as sitosteryl-β-D-(6-O-fattyacyl)-glucopyranoside (I). Its gross structure, as a monoester of sitosteryl-β-D-glucoside, was derived from a study of the products formed on methanolysis and on acid hydrolysis. The location of the fatty ester was established by comparison of the proton chemical shift for H₂C-6 in its tribenzoyl derivative with the chemical shifts for the corresponding protons in model benzoyl, acetyl and mixed benzoyl-acetyl derivatives of sitosteryl-β-D-glucopyranoside. The structure was confirmed by comparison, especially of optical rotation data, with a sample of sitosteryl-β-D-(6-O-stearoyl)-glucopyranoside prepared by synthesis. The [α]_D values for the natural (?45°) and the synthetic sample (?46.5°) are practically identical. Further there is good agreement between the molar rotation difference (ΔM_D) between (I) and its parent sitosterylglucoside and between the synthetic pair of glucoside and its ester.The approach to structure followed, in particular the use of ΔM_D comparisons, and the optical rotation data recorded in this paper, provide simple and convenient means for establishing the structure of other natural esterified sterol glycosides.     

The synthesis of 2,5-dideoxy-4,6-di-O-(2,3-dideoxy-α-D- erythro-hexopyranosyl)streptamine and 4,6-di-O(6-amino-2,3,6-trideoxy-α-D- erythro-hexopyranosyl)-2,5-dideoxystreptamine

The title pseudotrisaccharides, derived from 2,5-dideoxystreptamine, have been synthesized, in order to ascertain structure-activity relationships in aminoglycoside antibiotics. High yields of α-D-glycosides, virtually free of β anomers, were achieved by the BF₃-catalyzed addition of alcohols to glycals.     

Stereoselective synthesis of chirally deuterated (S)-D-(6-(2)H(1))glucose

Chirally deuterated (S)-D-(6-(2)H(1))glucose has been prepared in good overall yield from d-(6,6'-(2)H(2))glucose by a short, five-step synthesis from D-(6,6-(2)H(2))glucose utilizing (R)-(+)-Alpine-Borane [(R)-9-[(6,6-dimethylbicyclo[3.1.1]hept-2-yl)methyl]-9-borabicyclo[3.3.1]nonane]. Suitably protected methyl 2,3,4-tri-O-benzyl-D-(6,6-(2)H(2))glucopyranoside was prepared and the deuterated O-6 primary alcohol was oxidized to an aldehyde by Swern oxidation. Stereoselective reduction with nondeuterated (R)-(+)-Alpine-Borane gave methyl 2,3,4-tri-O-benzyl-(6S)-D-(6-(2)H(1))glucopyranoside, which was deprotected under standard conditions to afford the title compound. The key stereoselective reduction step was achieved in 90% yield. The preparation uses economical, commercially available starting materials and will be useful for elucidating biosynthetic mechanisms.     

Synthesis of 1-D- and 1-L-myo-inosityl 2-N-acetamido-2-deoxy-alpha-D-glucopyranoside establishes substrate specificity of the Mycobacterium tuberculosis enzyme AcGI deacetylase

Mycothiol (MSH, 1-D-myo-inosityl 2-(N-acetyl-L-cysteinyl)amido-2-deoxy-alpha-D-glucopyranoside) is the principal low molecular weight thiol in actinomycetes. The enzyme 1-D-myo-inosityl 2-N-acetamido-2-deoxy-alpha-D-glucopyranoside deacetylase (AcGI deacetylase) is involved in the biosynthesis of MSH and forms the free amine 1-D-myo-inosityl 2-amino-2-deoxy-alpha-D-glucopyranoside, which is used in the third of four steps of MSH biosynthesis. Here, we report the synthesis of two isomers of AcGI, which contain either 1-L-myo-inositol or 1-D-myo-inositol. These synthetic products were used to investigate substrate specificity of the Mycobacterium tuberculosis enzyme AcGI deacetylase.