Mechanism of Action of the Fungicide Thiabendazole, 2-(4′-Thiazolyl) Benzimidazole

Thiabendazole, 2-(4'-thiazolyl) benzimidazole (TBZ) inhibited the growth of Penicillium atrovenetum at 8 to 10 mug/ml. Oxygen consumption with exogenous glucose was inhibited at 20 mug/ml, but endogenous respiration required more than 100 mug/ml. TBZ inhibited completely the following systems of isolated heart or fungus mitochondria: reduced nicotinamide adenine dinucleotide oxidase, succinic oxidase, reduced nicotinamide adenine dinucleotide-cytochrome c reductase, and succinic-cytochrome c reductase at concentrations of 10, 167, 10, and 0.5 mug/ml, respectively. Cytochrome c oxidase was not inhibited. Antimycin A and sodium azide caused the usual inhibition patterns for both fungus and heart terminal electron transport systems. In the presence of antimycin, the fungicide inhibited completely succinate-dichloro-phenolindophenol reductase and succinate-2, 2-di-p-nitrophenyl-(3, 3-dimethoxy-4, 4-biphenylene-5, 5-diphenylditetrazolium)-reductase at 2 and 4 mug of TBZ per ml, respectively. Coenzyme Q reductase required 15 mug/ml. TBZ reduced the uptake by P. atrovenetum of glucose and amino acids and decreased the synthesis of various cell components. At 120 mug/ml, the incorporation of labeled carbon from amino acids-U-(14)C was decreased: lipid, 73%; nucleic acids, 80%; protein, 80%; and a residual fraction, 89%. TBZ did not inhibit peptide synthesis in a cell-free protein-synthesizing system from Rhizoctonia solani. Probably the primary site of inhibition is the terminal electron transport system and other effects are secondary.     

Cloning and characterization of a novel member of human β-1, 4-galactosyltransferase gene family

By using the EST strategy for identifying novel members belonging to homologous gene families, a novel full-length cDNA encoding a protein significantly homologous to UDP-Gal: N-acetylglucosamine β-1, 4-galactosyltransferase (GAlT) was isolated from a human testis cDNA library. A nucleotide sequence of 2 173 bp long was determined to contain an open reading frame of 1032 nucleotides (344 amino acids). In view of the homology to members of the galactosyltransferase gene family and especially the closest relationship to Gallus gallus GalT type I (CK I), the predicted product of the novel cDNA was designated as human β-1, 4-galactosyltransferase homolog I (HumGT-H1). Its mRNA is present in different degrees in 16 tissues examined. Southern analysis of human genomic DNA revealed its locus on chromosome 3.     

Synthesis of β-1, 3-Glucan and β-1, 3 and β-1, 4-Mixed Glucan from UDP-α-d-Glucose

A particulate enzyme preparation from Phaseolus aureus (mung bean) seedlings catalyzed the synthesis of a water insoluble β-1,3-glucan from UDP-α-d-glucose (UDPG) at high concentrations (0.4~20 mm) and an alkaline insoluble β-1,3 and β-1,4-mixed glucan from UDPG at a low concentration (8.5 µm).

Furthermore, the two kinds of β-glucan synthetases which were investigated with two reaction systems at high and low concentrations of UDPG had different properties in optimal pH, stability of enzyme activity, and metallic ion requirement.     

Crystal structure of 4-(N-acetyl,2,3,4-tri-O-acetyl-β-l-arabinopyranosylamino)azobenzene

The crystals of the title compound, C₂₅H₂₇N₃O₈ (M_r497.55), are monoclinic, space group P2₁ with a = 11.680(2), b = 8.089(1), c = 13.804(3) Å, β = 92.52(2)°, V = 1302.7 ų, and Z = 2; D_c = 1.27 g.cm⁻³. The structure was solved by using direct methods. The refinement of all non-hydrogen atom parameters yielded R = 0.050. The compound has normal geometry with the ¹C₄ conformation of the pyranoid ring and the extended trans conformation of the azobenzene moiety.     

Effects of cAMP,theophylline, imidazole,and 4-(3,4-dimethoxybenzyl)-2-imidazolidone on the leaf movement rhythm of Trifolium repens—a test of the cAMP-hypothesis of circadian rhythms

The period length of the leaf movement rhythm of Trifolium repens L. is lengthened by continuously offered cAMP (0.5–1.0 mol m^-3) and theophylline (0.5–4 mol m^-3). At the higher concentrations this effect is more pronounced and the rhythm damps out faster. Imidazole (0.5 and 1 mol m^-3) has no effect on the period length; however, after 5 mol m^-3 the rhythm is abolished. Offered as 4 h pulses the resulting phase response curves for cAMP and imidazole are similar and show delays of up to 4 h during the day position of the leaves. Theophylline pulses lead to delays of up to 5 h during closure and advances of up to 3 h during opening. No phase shift is brought about by 4-(3,4-dimethoxybenzyl)-2-imidazolidone. The results do not support the cAMP-model of the circadian clock which has been proposed by Cummings (J. theor. Biol. 55, 455–470; 1975). The effect of the substances tested could, however, be based upon influences on the transport of Ca²⁺.Abbreviations ATP adenosine triphosphate - cAMP cyclic adenosine 35 monophosphate - AMP adenosine 5 monophosphate - AC adenyl cyclase - PDE phosphodiesterase - LL continuous light     

Occurrence of Endogenous Pollen Growth Inhibitors, 4-Hydroxybenzoic Acid and 4-(β-D-Glucopyranosyloxy)benzoic Acid,in the Pollen of Pinus densiflora†

A Pseudomonas strain capable of using pyrazinamide as the sole source of nitrogen was isolated from soil. An aromatic amidase from the bacterium was purified 400-fold to homogeneous on polyacrylamide gel electrophoresis. The enzyme had a molecular weight of 43,000 by gel filtration on Sephadex G-150 and consisted of two identical subunits. The isoelectric point was at 4.45. Among the compounds tested, pyrazinamide (relative activity, 100%), nicotinamide (60%), and 5-methylpyrazinamide (3.4%) were hydrolyzed at considerable rates. Benzamide, picolinamide, and isonicotinamide were not substrates. Apparent Km of the enzyme for pyrazinamide and nicotinamide were 5.6 × 10 ^?5 m and below 5 × 10^?6 m, respectively. The enzyme was not able to hydrolyze aliphatic amides. The enzyme was most active between pH 6.5 and 10 and 75°C, and was stable between pH 5.5 and 8.5 and below 45°C.     

Metabolism of (2Z,4E)-γ-Ionylideneethanol and (2Z,4E)-γ-Ionylideneacetic Acid in Cercospora cruenta

[2–¹⁴C]-(2Z,4E)-γ-Ionylideneethanol and [2–¹⁴C]-(2Z,4E)-γ-ionylideneacetic acid were converted by Cercospora cruenta to [2–¹⁴C]-(2Z,4E)-1′,4′-dihydroxy-γ-ionylideneacetic acid and [2-¹⁴C]-(2Z,4E)-4′-hydroxy-γ-ionylideneacetic acid, which are intermediates of ABA biosynthesis in C. cruenta.     

The structure, properties, and nature of unconventional π halogen bond in the complexes of Al 4 2- and halohydrocarbons

Quantum chemical calculations have been performed to study the all-metal π halogen bonding in Al(4)(2-)···halohydrocarbon complexes. The result shows the existence of the all-metal π halogen bond in the complexes. There are three interaction modes (top, corner, and side) between Al(4)(2-) and halohydrocarbon. The interaction energy of this interaction varies from a positive value to -90.54 kJ mol(-1) in Al(4)(2-)···I-ethyne-s complex. The interaction strength is affected greatly by the hybridization of C atom and follows the order of C(sp(3)) < C(sp(2)) < C(sp) in most complexes. The methyl group in the halogen donor plays a negative contribution to the formation of halogen bond. The halogen bonding becomes stronger for the heavier halogen atom. The effect of binding site on the strength of halogen bond is related with the nature of halogen atom. The complexes have been analyzed with electrostatic potential, NICS, ELF, NBO, and AIM.     

Biopolymer - Surfactant Interaction: 4 Kinetics of Binding of Cetyltrimethyl Ammonium Bromide with Gelatin,Hemoglobin, β-lactoglobulin and Lysozyme

Abstract

The binding of CTAB with the proteins, gelatin, hemoglobin, β-lactoglobulin and lysozyme follow first order kinetics and occurs either in two or three distinct stages. The number of stages depends on the overall configuration of the biopolymers. The denatured protein, gelatin has shown three-stage kinetics under all conditions, whereas the native proteins, hemoglobinn, β-lactoglobulin and lysozyme have exhibited two stage kinetics. Heat treated lysozyme in 8 mol dm-³ urea medium has also shown a two-stage kinetics. On the basis of non interacting binding sites on the proteins and independent sequential binding, the rates of reaction have been observed to increase with temperature and follow the trend k₁ >> k₂ > k₃. The interaction of CTA⁺ with the proteins is both electrostatic and hydrophobic. Hemoglobin has shown maximum reaction rate whereas, β-lactoglobulin has shown a minimum. The activation parameters for the kinetic process have exhibited almost non-variant Δ G? and Δ H? < T Δ S? The formation of activation complex in the Eyring model is entropy controlled so also the overall kinetics. An isokinetic entropy-enthalpy compensation phenomenon has been observed for the respective kinetic stages.     

The biotransformation of α-(2, 4, 6-trimethylphenyl) ethylamine by rabbit liver preparations

Microsomal incubation of the parent amine, α-(2, 4, 6-trimethylphenyl) ethylamine, VI, produced imine, II, alcohol, IV, oxime, V, and several unknowns. The isolation of imine, II, produces evidence that imines may be involved in the microsomal deamination of primary amines. Separate incubations of the imine, II, produced oxime, V, and several unknowns, one of which is tentatively identified as the nitro derivative. Incubation of the oxime, V, gave the alcohol, IV, the “nitro” metabolite as above and 2 unknowns. Incubation of the hydroxylamine, VII, gave oxime, V, alcohol, IV, 2 unknowns and the “nitro” metabolite.     

Production of zearalenone-4-glucoside,a-zearalenol-4-glucoside and ß-zearalenol-4-glucoside

The work at hand describes the production of the zearalenone (ZON) metabolites zearalenone-4-glucoside (ZON-4G), a-zearalenol-4-glucoside (oc-ZOL-4G) and ß-zearalenol-4-glucoside (ß-ZOL-4G). In a first step a genetically modified yeast strain, expressing theArabidopsis thaliana UDP-glu-cosyltransferase UGT73C6, was treated with ZON to produce ZON-4G. The substance was purified by solid phase extraction and subsequent reversed phase preparative HPLC prior to the reduction with sodium borohydride to yield 0C-ZOL-4G and ß-ZOL-4G. The identity and purity of the substances were confirmed by¹³C-and¹H-NMR as well as by HPLC-UV. In total, 50 mg of ZON were used to produce 5 mg of a-ZOL-4G with a purity of 98%, 6 mg of ß-ZOL-4G with a purity of 99% and 5 mg of ZON-4G with a purity of 99%.     

Synthesis of 1-(4-Keto-2, 3-O-isopropylidene-α-L-rhamnopyranosyl) uracil

Abstract

Synthesis of 1-(2, 3, 4-tri-0-acetyl-α-L-rhamnopyranosyl) uracil (3), 1-(α-L-rhamnopyranosyl) uracil (4), 1-(2, 3-0-isopropylidene-α-L-rhamnosyl) uracil (5), and 1-(2, 3-0-isopropylidene-4-keto-α-L-rhamnopyranosyl) uracil (6) are reported. Oxidation of (5) to (6) was effected using pyridinium chlorochromate in presence of molecular sieves.     

Cell-free conversion of 4-γ,γ-dimethylallyltryptophan to 4-[4-hydroxy-3-methyl-Δ2-butenyl]-tryptophan in Claviceps purpurea PRL 1980

The conversion of 4-γ,γ-dimethylallyltryptophan to 4-[4-hydroxy-3-methyl-Δ²-butenyl]-tryptophan was catalyzed by the 60–80% ammonium sulphate fraction from Claviceps purpurea PRL 1980. The conversion was stimulated by NADPH. Two major unidentified products in the incubation mixture were not significantly incorporated into elymoclavine when they were added to cultures of C. purpurea PRL 1980.     

Incorporation of shikimate and 4-(2′-carboxyphenyl)-4-oxobutyrate into phylloquinone

The patterns of incorporation of d-[G-¹⁴C]shikimate and variously labelled ¹⁴C-4-(2′-carboxy-phenyl)-4-oxobutyrate into the naphthoquinone nucleus of phylloquinone by maize shoots have been investigated. The results show that (a) the alicyclic ring and C-7 of shikimate give rise to Ring A and either C-1 or C-4, and (b) the phenyl ring, 2′-carboxy and C-4, and C-2 and -3 of 4-(2′-carboxyphenyl)-4-oxobutyrate give rise to Ring A, C-1 and -4 and C-2 and -3. Radioactivity from α-[1-¹⁴C]naphthol, 1,4-[1,4-¹⁴C]naphthoquinone and [Me-¹⁴C]menadione is not incorporated into phylloquinone to any significant extent.     

Proteolytic inactivation of 1, 4-α-d-glucan 6-α-d-glucosyltransferase purified from Aspergillus niger R-27

An extracellular 1,4-α-d-glucan 6-α-d-glucosyltransferase [d-glucosyltransferase, 1,4-α-d-glucan:1,4-α-d-glucan(d-gluco 6-α-d-glucosyltransferase, EC 2.4.1.24] from Aspergillus niger R-27 has been purified and the kinetics of its proteolytic inactivation with subtilisin studied. The purified enzyme was shown to be homogeneous using disc polyacrylamide gel electrophoresis. It contained 16.0% mannose, 0.19% glucose and 2.95% 2-acetamido-2-deoxy-d-glucose. The characteristic feature of the proteolytic degradation of glucosyltransferase is rapid hydrolysis of ～12 peptide bonds per mol and the formation of an active intermediate product which is more resistant to further proteolysis, but is easily heat-inactivated. The isolation and some properties of glucosyltransferase are also described.     

Synthesis and immunological evaluation of the 4-β-glucoside of HMBPP

HMBPP ((E)-4-hydroxy-3-methyl-2-butenyl pyrophosphate) is a highly potent innate immunogen that stimulates human γδ T cells expressing the Vγ2Vδ2 T cell antigen receptor. To determine if glycoside conjugates of HMBPP retain activity, the 4-β-glucoside and its acetylated homolog were synthesized and tested for their ability to stimulate γδ T cells. The glycoside HMBPP conjugate stimulated human γδ T cells with an EC(50) of 78nM. The tetraacetyl glycoside HMBPP conjugate was also active (EC(50)=360nM). The two isomeric mono-β-glucosides of the parent (E)-2-methylbut-2-ene-1,4-diol, however, were not active. Thus, HMBPP glycosylated at the 4-OH position stimulates γδ T cells as long as the pyrophosphate moiety is present.     

Distribution of a Betaine Lipid O-(1,2-Diacylglycero)-4′-(N,N,N-Trimethyl)homoserine in Tissues of Some Lycopodiophyta Species

The distribution of O-(1,2-diacylglycero)-4-(N,N,N-trimethyl)homoserine (DGTS), a betaine lipid, in ten samples of plants belonging to the division Lycopodiophyta collected in various habitats was studied. Homogeneous plant tissues (vegetative shoots and spikelets) and mixed tissues (shoots with spikelets) were analyzed. A particular attention was paid to the DGTS-synthesizing ability of various club mosses, various tissue types forming an organ in a single plant species, as well as the ratio between DGTS and other glycerolipid classes.     

Fragmentation of realgar,As4S4, controlled by transition metalligand systems

The chemical behavior of the realgar molecule, As₄S₄, toward various (triphos)M moieties has been investigated. The reaction of As₄S₄ with [{MCl(cod)}₂] (M=Rh or Ir; cod=1,5-cyclooctadiene) in the presence of the ligand triphos [triphos=1,1,1- tris(diphenylphosphinomethyl)ethane] yields compounds of formula [(triphos)M(η³-As₃S₃)]·C₆H₆ containing the new As₃S₃ unit, which is trihapto bonded to the metal atom through one sulfur and two arsenic atoms. Such a As₃S₃ fragment is the largest one so far extruded from the realgar molecule. The As₄S₄ molecule undergoes more drastic disruptions in the reactions with Co(BF₄)₂·6H₂O and Ni(BF₄)₂·6H₂O in the presence of triphos. These results suggest that the fragmentation of the As₄S₄ molecule is controlled by the nature of the metal atom involved in the reaction.