bluuebunny/crossref_metadata_2025 huggingface dataset:
Mass spectra of ar-nitrostyrenes
Authors: Middleton S , Butcher M , Mathews RJ
Published: November 2018

The mass spectra of m- and
p-nitrostyrene are relatively simple but that of the ortho isomer is quite
complicated due to the intervention of numerous fragmentation pathways which
involve interaction between the nitro and vinyl groups.
Methyleneketenes and methylenecarbenes. IV. Pyrolysis of 5-Heteroarylmethylene-2,2-dimethyl-l,3-dioxan-4,6-diones to give phenolic benzothiophens, benzofurans and indoles
Authors: Baxter GJ , Brown RFC , McMullen GL
Published: November 2018

The synthetic sequence
leading from o-tolualdehyde to 2-naphthol1 has been applied to seven
five membered heterocyclic aldehydes bearing adjacent methyl substituents.
Flash vacuum pyrolysis of the corresponding
5-heteroarylmethylene-2,2-dimethyl-1,3-dioxan-4,6-diones gave hydroxy
derivatives of the benzologous systems benzothiophene,
benzofuran, dibenzofuran, indole and carbazole in 54-98% yield.
Interaction of dicyandiamides with thioamides: Formation of 6-Alkyl(or aryl)-4-amino(or arylamino)-1,3,5-triazine-2-thiols and Amidino(or aryamidino)thioureas
Authors: Joshua CP , Rajan VP
Published: November 2018

The reactions of
thioacetamide and thiobenzamide with dicyandiamide
and aryldicyandiamides in the presence of hydrochloric acid have been found to
yield the related 6-alkyl(or aryl)-4-amino(or arylamino)-1,3,5- triazine-2-thiols
and amidino(or arylamidino)thioureas. The formation
of these compounds is accounted for by a mechanism involving the initial
formation of a monosulphide. By rearrangement and subsequent cyclization with
elimination of ammonia it forms the 1,3,5-triazines, whereas its decomposition
yields amidinothiourea and the related nitrile. Synthesis of certain of these 1,3,5-triazine-2-thiols
has been carried out by the stepwise replacement of all the chlorine atoms in 2,4,6-trichloro-1,3,5-triazine
with methyl or phenyl, arylamino and mercapto groups.
Baeyer-Villiger oxidation of 6β-Bromocholest-4-en-3-one
Authors: Ahmad MS , Shafiullah  , Mushfiq M
Published: November 2018

Oxidation of 6β-bromocholest-4-en-3-one
(1) with perbenzoic acid (p- toluenesulphonic acid as catalyst) provided
6β-bromo-3-oxa-A- homocholest-4a-en-4-one (2) and a bromine free γ-lactone
methyl ester (3). The structures (2) and (3) are supported by their spectral
properties.
Occurrence of some unusual compounds in the leaf oils of Eriostemon obovalis and Phebalium glandulosum subsp. glandulosum
Authors: Lassak EV , Southwell IA
Published: November 2018

The steam-volatile leaf
oils of Eriostemon obovalis A. Cunn.
and Phebalium glandulosum subsp. glandulosum Hook. (Rutaceae) contain substantial amounts of methyl p-methoxycinnamate and(+)-2,6- dimethyloct-7-en-4-one
respectively.
Photochemistry of Hemicyclone Diels-Alder Adducts of Substituted Benzoquinones
Authors: Coxon JM , Oconnell MJ , Steel PJ
Published: November 2018

The Diels -Alder reactions between hemicyclone and a number of substituted benzoquinones are reported. Photolysis of the products produces pentacyclo [5,4,0,02,6,03,10,05,9] undecane derivatives and/or 2- oxapentacyclo [6,4,0,01,4,03,7,05,9] dodecane derivatives depending on the substituents. X-ray crystal structures of oxetan (8) and cyanohydrin (33) are also reported.
Structure and Conformations of Gaba-Transaminase Inhibitors. I. Multisubstrate Analogs
Authors: Andrews PR , Cody V , Iskander MN , Jeffrey AI , Mackay MF , Oliver PJ , Sadek M
Published: November 2018

Two multisubstrate analogues of the transition state in the reaction catalysed by the enzyme GABA- transaminase (E.C. 2.6.1.19), sulfonic acid pyridoxal dervative , C10H16N2O5S (1) and carboxylic acid pyridoxal derivative, C13H18N2O4 (2), have been characterized by X-ray analyses of crystals of (1). HCl , (1).H2O and (2). HCl . In each structure, the nitrogen on the side chain is the donor in intramolecular hydrogen bonding. However, it is only in (2). HCl that this interaction is with the phenolic oxygen as postulated in the proposed transition state of the reaction catalysed by GABA- transaminase . For both structures of (1), on the other hand, this interaction is with the oxygen of the ring hydroxymethyl substituent, and results in a seven- membered ring. Conformational analysis indicates that both modes of hydrogen bonding may be present in the pyridoxal derivatives, although no quantitative assessment is possible at the MINDO/3 or MNDO levels. Simple classical potential energy calculations indicate significant structural differences between the lowest energy conformations of these compounds and the calculated transition state. However, conformations which match the key features of the transition state are also relatively low in energy.
The Chlorination of 2,3-Dimethylphenols, 2,5-Dimethylphenols and 2,6-Dimethylphenols and 2,3,4,5-Tetrachloro-6-Methylphenol; Some Structural Studies of Polysubstituted Cyclohex-2-Enones and Cyclohex-3-Enones
Authors: Hartshorn MP , Martyn RJ , Robinson WT , Vaughan J
Published: November 2018

The chlorination of 2,5-dimethylphenol (4) gives the polychlorocyclohex-3-enones (10),(11) and (12), the chlorodienone (13) and the polychlorocyclohex-2-enones (14) and (15). Chlorination of 2,3- dimethylphenol (5) gives the isomeric polychlorocyclohex-3-enones (18), (19) and (20), while the chlorination of 2,6-dimethylphenol (9) gives the C2-epimeric pentachlorocyclohex-3-enones (7) and (8). X-ray structure analyses are reported for compounds (12), (14), (15), (18), (19) and (20). The structural features which determine the preferred conformations of these polychloro cyclohex-3-enones and cyclohex-2- enones are discussed.
The Constituents of Marine Sponges. II. The Isolation From Aplysilla rosea (Dendroceratida) of (5R*,7S*,8R*,9S*,10R*,13S*,14S*,15S*)-15 ,17-Epoxy-17-Hydroxy-16-Oxospongian-7-Yl Butyrate (Aplyroseol-1) and Related Diterpenes (Aplyroseol-2 to Aplyroseol-6)
Authors: Karuso P , Taylor WC
Published: November 2018

From the red-pink encrusting marine sponge Aplysilla rosea Barrois eight spongian diterpenes were isolated. Aplyroseol-1 was shown by spectroscopic methods to be (5R*,7S*,8R*,9S*,10R*,13S*,14S*,15S*)-15,17-epoxy-17-hydroxy-16-oxospongian-7-yl butyrate (5) and aplyroseol -2 to -6 to be (6)-(10) respectively. Two lactones (11) and (12), ambliofuran and its hexahydro derivative were also identified. A steroid fraction was also isolated.
The Chemistry of Eremophila Spp. XXV. New Cembrene Derivatives From E. dempsteri, E. platycalyx and E. fraseri
Authors: Ghisalberti EL , Jefferies PR , Mori TA
Published: November 2018

The isolation and structural elucidation of three new cembrene diterpenes from Eremophila species is reported. (1R,3Z,7E,11Z)-15- Hydroxycembra-3,7,11-trien-19-oic acid
(3) and (1R,3Z,8ξ,11Z)-15- hydroxycembra-3,11-dien-19-oic acid (4) were isolated from E. dempsteri and (1R,3S,4R,7E,11Z)-3,15-epoxy-19-oxocembra-7,11-dien-18-ol as the malonate half ester derivative (15) was isolated from E. Platycalyx and a variety of E. Fraseri. In addition the preparation of (1R,3Z,7Z,11Z)- cembra-3,7,11,15-tetraene (13; all- cis-cembrene-A ) is reported.
Guidelines for the Publication of Research in Experimental Organic Chemistry
Authors: Drenth W
Published: November 2018

Guidelines for the description of experimental procedures, for the characterization of compounds, and for the presentation of derived physico-chemical quantities and mechanistic interpretation are formulated. These Guidelines are recommended as a minimum set for the publication of research in experimental organic chemistry.
The Chemistry of 5-Oxodihydroisoxazoles. III. Synthesis of Further Annelated Pyrimidines
Authors: Prager RH , Rosenzweig TK , Singh Y
Published: November 2018

The synthesis of some 2-heterocyclyl-5-oxo-2,5-dihydroisoxazole-4-carboxylates is reported, where the heterocycle is pyridin-2-yl, triazin-2-yl, pyrimidin-4-yl, quinolin-2-yl or phthalazin- 1-yl, as is their base-catalysed rearrangement to the corresponding annelated pyrimidines.
Viroallosecurinine and ent-Phyllanthidine From the Leaves of Breynia coronata (Euphorbiaceae)
Authors: Lajis NH , Guan OB , Sargent MV , Skelton BW , White AH
Published: November 2018

Extraction of the fresh leaves of Breynia coronata has yielded the Securinega alkaloids viroallosecurinine (4) and ent-phyllanthidine (6).
Structure of [(tmpp)2Ag]+2[Ag5I7]2-; an Unusual Ionic Adduct of Tris(2,4,6-trimethoxyphenyl)phosphine (tmpp) With Silver(I) Iodide
Authors: Baker LJ , Bowmaker GA , Effend y , Skelton BW , White AH
Published: November 2018

A single-crystal structure determination is reported for [( tmpp )2Ag]+2 [Ag5I7]2-, a product isolated from the reaction of the highly basic, sterically hindered tertiary phosphine ligand tris (2,4,6-trimethoxypheny1) phosphine ( tmpp ) with silver(I) iodide. This complex is triclinic, P1, a 22.01(2), b 19.98(1), c 16.48(1) � , α 94.49(6), β 92.46(7), γ 116.76(5)',Z 2; R was 0.11 for 3436 'observed' reflections. The asymmetric unit contains two crystallographically inequivalent [( tmpp )2Ag]+ cations in which the silver atoms are quasi-linearly coordinated to two phosphorus atoms with P-Ag-P angles of 175.9(9) and 179(1)°, and a mean Ag-P distance of 2.38 � . The anion has a novel one-dimensionally polymeric structure which is based on a double-stranded 'ladder' polymer of AgI units to which are bonded one I- and one AgI2-unit for every four AgI units. In the resulting polymer, all silver atoms are four-coordinate, while iodide coordination numbers of two, three and four are observed, with associated Ag-I distances of 2.75-2.86(1), 2.72-2.91(1) and 2.90-3-08(1) � respectively.
14N Nuclear Magnetic Resonance Relaxation of the Nitrate Ion and Ion Pairing in Aqueous Solution
Authors: Owens G , Guarilloff P , Steel BJ , Kurucsev T
Published: November 2018

14 N n.m.r. spin-lattice relaxation times of four metal nitrate salts were measured as a function of concentration in aqueous solution. The concentration dependence of T1 was attributed to the formation of ion pairs with increasing concentration in these solutions. The T1 data, allowing for viscosity corrections, were treated by a two-state model of 'free' and 'bound' nitrate ions and to both possibilities of slow and fast exchange between the two states. In the equilibrium expressions estimates of the relevant activity coefficients were included. The slow nitrate exchange mechanism was favoured and the values obtained for this particular mechanism compared well with those derived from alternative measurements.
Cascade Radical Cyclization-Fragmentation-Transannular-Ring Expansion Reactions Involving Oximes. A New Approach to Synthesis of Angular Triquinanes
Authors: Hollingworth GJ , Pattenden G , Schulz DJ
Published: November 2018

Treatment of the acetylene-substituted cyclobutanone oxime ether (13) with (Me3Si)3SiH leads, in one pot, to the 5,6-bicyclic enone oxime (14) in 70% yield. It is suggested that the formation of (14) from (13) proceeds by way of a novel double ring expansion-transannulation process involving aminyl radical intermediates (see Scheme 3, below). By contrast, treatment of the cyclobutanone (3a) with Bu3SnH instead leads only to the product (11) of hydrostannylation of the acetylene unit in (3a). Neither (3a) nor (13) produced any of the expected bicyclo[3.3.0]octane products, viz. (5a) and (15), following treatment with silanes or stannanes. When a solution of the vinyl bromide-substituted cyclobutanone oxime (42) was irradiated with a sunlamp in the presence of (Me3Si)3SiH, the main product isolated was the triquinane (45) (38%) resulting from a cascade radical 6-exo-trig cyclization, aminyl radical fragmentation, 5-exo-trig radical transannulation, 5-exo-trig cyclization sequence.
Synthesis and Structure Determination of Gibberellin-Derived Antheridiogens From Fern Gametophytes of the Lygodium Genus
Authors: Furber M , Kraftklaunzer P , Mander LN , Pour M , Yamauchi T , Murofushi N , Yamane H , Schraudolf H
Published: November 2018

Two successful and two unsuccessful synthetic routes are described for the conversion of commercially available fungal gibberellins to the antheridiogen GA73 methyl ester (5), originally isolated from gametophytes of the fern Lygodium japonicum. The more efficient route began with the Birch reduction of either the GA7 derivative (31) or methyl gibberellate 3,13-dimesylate (32) to give the ∆1(10),16-diene acid (33), which was converted into the ∆1,9-diene acid (40) by means of a four step procedure. This intermediate could be selectively hydrogenated to the ∆9-ene derivative which underwent iodolactonization and then elimination of HI to afford enone (29), Wittig methylenation of which furnished the target antheridiogen (5). In addition, (29) was functionalized at C12 by free radical bromination to give access to the 12β-hydroxy derivative of (5), i.e. (6), a new antheridiogen isolated from Lygodium circinnatum.
The Cyclization of Hex-5-Enylcarbamates and Related Compounds With Benzeneselenenyl Chloride and Some Reactions of the 2-Substituted Piperidine Products
Authors: Morella AM , Ward AD
Published: November 2018

The reaction of hex-5-enylcarbamates with benzeneselenenyl chloride gives adducts which cyclize , in the presence of silica or stannic chloride, to 2-phenylselenomethylpiperidine-1-carboxylates. The corresponding selenoxides eliminate to form 2-methylenepiperidine derivatives which are unstable, both thermally and on silica. The selenoxides also undergo a Pummerer-type reaction to form 2-acetoxy( phenylseleno ) methylpiperidine systems which can be oxidatively converted into a piperidine 2-aldehyde. The selenoxides react with carbon tetrachloride in base to form a 2,2,2-trichloroethyl substituent . Both the selenoxides and the phenylseleno groups of the cyclized products can be displaced by nucleophiles. Ethyl hept-6-enylcarbamate did not give a cyclic product with benzeneselenenyl chloride and silica, and gave a poor yield of a hexahydroazepine with stannic chloride. Hex-5-enamide cyclized to give a lactone, rather than a lactam , product. Hex-5-enenitrile gave Ritter reaction products with benzeneselenenyl chloride in acetonitrile , and a dimer in non- nucleophilic solvents.
Studies on Aromatic Trichromophore Systems Incorporating Anthracene Moieties. III. Crystal Structures of 2-(9-Anthryl)-1-(9-anthrylmethyl)ethyl 2-(9-Anthryl)ethyl Succinate (A2A) and 2-(9-Anthryl)ethyl Acetate (AM) and Their Fluorescence in the Solid State
Authors: Cotrait M , Allouchi H , Marsau P , Nourmamode A , Grelier S , Castellan A
Published: November 2018

The structures of 2-(9-anthryl)-1-(9-anthrylmethyl)ethyl 2-(9 anthryl )ethyl succinate (A2A) and 2-(9-anthryl)ethyl acetate (AM) have been determined by X-ray diffraction, and the molecular fluorescence of the crystals has been established. The A2A crystal is triclinic while the AM crystal is monoclinic. A2A: Pī , a 18.514(5), b 11.802(3), c 10.836(3) Ǻ; α 99.63(2), β 85.75(2), γ 79.67(2)°, R 0.053 for 3547 observed reflections. AM: P21/c, a 12.566(2), b 12.991(2), c 8.805(2) Ǻ, β 97.84(1)°, R 0.040 for 1519 observed reflections. For the A2A molecule as for the previously studied A2PHEN and A2SC (see Part II), the bisanthracene moiety and a large part of the ester chain show similar conformations. The crystal cohesion is due to numerous van der Waals interactions in both compounds and to π intermolecular overlap between the anthracene moieties of neighbouring molecules of AM. The fluorescence emission of the AM crystal is of excimer type and correlates with the intermolecular stacking of the anthracene rings. In contrast, the emission from the A2A crystal was found to be very weak and with some similarity with the emission of the dilute solution. This is probably due to defects, not accounted for by the X-ray determination, permitting intramolecular interactions in the solid.
The Cycloaddition Reactions of Benzimidazole-2-carbonitrite Oxide With Alkenes
Authors: Cundy DJ , Simpson GW
Published: November 2018

Benzimidazole-2-carbonitrile oxide was prepared in situ and reacted with vinyl acetate, acrylonitrile, styrene, phenyl vinyl sulfone and 3,3,3-trifluoropropene to afford 2-(5'-acetoxyisoxazolin-3'-yl)-, 2-[(5'-cyanoisoxazolin-3'-yl)-, 2-(5'-phenylisoxazolin-3'-yl)-, 2-[(5'-phenylsulfonyl)isoxazolin-3'-yl]- and 2-[(5'- ( trifluoromethyl )isoxazolin-3'-yl)]- benzimidazole respectively. 2-(5'-Acetoxyisoxazolin-3'-yl) benzimidazole was converted into 2-(isoxazol-3'-yl) benzimidazole by treatment with triethylamine. The amidoximes derived from unsubstituted and N1-sulfamoyl-substituted 2-cyanobenzimidazoles were prepared but were not preparatively useful as precursors to benzimidazole-2-carbonitrile oxides.
Rhenium Diamino Dithiolate Complexes. II. The X-Ray Crystal Structure of an N-Alkylated Derivative: Oxo(1,1,8,8-tetramethyl-3-hexyl-3,6-diazaoctane-1,8-dithiolato)rhenium(V)
Authors: Jackson TW , Kojima M , Lambrecht RM , Craig DC , Rae AD
Published: November 2018

The complex oxo(1,1,8,8-tetramethyl-3-hexyl-3,6-diazaoctane-1,8-dithiolato)rhenium(V) was prepared, and the crystal structure was determined by X-ray crystallography. This compound was more lipophilic than the previously published oxo(1,1,8,8-tetraethyl-3,6-diazaoctane-1,8-dithiolato)rhenium(V) (1c).
Compressibility of Molecular Liquids and Liquid Mixtures
Authors: Goharshadia EK , Boushehri A
Published: November 2018

The linear pressure dependence of the bulk modulus of selected molecular liquids and liquid mixtures has been investigated by using equations of state based on statistical-mechanical theory. The calculated values of the bulk modulus for N2, Ar+N2 and Kr+Xe are in good agreement with reliable experimental data.
Low-Temperature Structure and Magnetic Properties of Tetraphenylarsonium Tetrachloronitridotechnetate(VI)
Authors: Figgis BN , Reynolds PA , Larsen FK , Williams GA , Delfs CD
Published: November 2018

The crystal structure of [As(C6H5)4] [TcNCl4] was determined at 120 K by X-ray diffraction and at 28 K by neutron diffraction. The crystals are tetragonal, space group P4/n, with a 1260.4(3) and c 773.2(2) pm at 120 K. The [TcNCl4]-anion possesses exact C4v symmetry, with Tc≡N distances of 160.3(2) and 162.5(4)pm at 120 and 28 K respectively. Magnetic susceptibilities were measured on single crystals from 300 to 4.5 K. The results indicate a well behaved S ½ system following the Curie-Weiss law with θ -0.13 K
Synthesis, Characterization and Reactions of the Chiral Transfer Agent Dicarbonyl(triphenylphosphine)-[(4r)-phenyl-(1'r)-(1'-phenylethyl)-1-azabuta-1,3-diene]iron(0)
Authors: Kanemaguire LAP , Pyne SG , Siu AFH , Skelton BW , White AH
Published: November 2018

The synthesis and room temperature single-crystal X-ray structural characterization of the title compound [( PhCH =CHCH= NCHMePh )Fe(CO)2(PPh3)] are described, the first optically pure 1-azabuta-1,3-diene adduct of iron(0) to be so recorded. Crystals are orthorhombic, P212121, a 20.197(6), b 14.09(1), c 11.094(5) Ǻ, Z 4; conventional R on |F| was 0.061 for 2217 independent 'observed' (I> 3σ(I)) reflections. This compound has been employed to transfer the Fe(CO)2(PPh3) moiety to cyclic 1,3-dienes to give new complexes, including the first example of optically active dicarbonyl ( triphenyl - phosphine )(η4-1-methoxycyclohexa-1,3-diene)iron.
The Syntheses of [M(C5Ph5)2]n+ (N=0,1) Complexes of Nickel, Iron and Chromium. The Structures of the Decaphenylmetallocenium Cations of Nickel and Iron
Authors: Field LD , Hambley TW , He T , Humphrey PA , Lindall CM , Masters AF
Published: November 2018

Decaphenylnickelocene is isolated from the reaction between [Ni(CO)2(PPh3)2], 5-bromo-1,2,3,4,5-pentaphenylcyclopenta-1,3-diene and zinc dust. Decaphenylnickelocene is obtained as air-stable crystals, insoluble in most common solvents. It can be oxidized by bromine or by nitronium tetrafluoroborate to the decaphenylnickelocenium cation, which can be chemically reduced to decaphenylnickelocene. The decaphenylnickelocenium cation is characterized spectroscopically and its crystal structure, as its tribromide and tetrafluoroborate salts, is reported. The structures are compared with that of decaphenylferrocenium tribromide, which is formed by bromine oxidation of decaphenylferrocene. Decaphenylchromocenium tribromide is prepared by bromine oxidation of decaphenylchromocene, which is prepared from [Cr(MeCN)3(CO)3], pentaphenylcyclopentadienyl bromide and zinc dust.
Reactivities of Piperazine-2,5-diones in Radical Bromination Reactions
Authors: Chai CLL , Hockless DCR , King AR
Published: November 2018

The reactivities of various N,N'- diacetylated piperazine-2,5-diones towards radical bromination reactions are reported. The studies show that glycyl centres of piperazine-2,5-diones are more reactive towards radical bromination reactions compared to α-substituted amino acid centres. In addition, large differences in reactivities were observed for the cis and trans isomers of N,N'-diacetylated alanine anhydride. Single-crystal structure determination of each isomer revealed that conformational effects may account for the difference in chemical reactivity.
Butlerins D, E and F-Three New Hexasubstituted Lichen p-Terphenyls
Authors: Elix JA , Elix JA , Ernstrussell MA , Ernstrussell MA
Published: November 2018

Butlerin D (4) (3',4,4",5',6'-pentamethoxy[1,1':4',1"-terphenyl]-2'-yl acetate), butlerin E (5) (3',4,4'6'-tetramethoxy[1,1':4',1"-terphenyl]-2',5'-diyl diacetate ) and butlerin F (6) (3',4,4",5'- tetramethoxy [1,1":4',1"-terphenyl]-2',6'-diyl diacetate ) have been synthesized and shown to co-occur with usnic acid, butlerin A (1), butlerin B (2) and butlerin C (3) in the lichen Relicina connivens.
Crystal and Molecular Structure of mer-cis-(PEt2Ph)2(PPri3)H-trans-Cl2IrIII
Authors: Ditzel EJ , Griffiths KD , Robertson GB
Published: November 2018

The structure of mer-cis-(PEt2Ph)2(PPri3)H-trans-Cl2IrIII (4) has been determined by single-crystal X-ray diffraction analysis. Crystals are monoclinic, space group P21/c, with a 11.607(1), b 21.553(1), c 14.066(1) Ǻ, β 109.04(1)? and Z 4. Structure refinement by full-matrix least-squares analysis (3244 unique reflections, 316 parameters) converged with R 0.034 and Rw 0.041. The PEt2Ph ligands are similarly disposed to their PMe2Ph counterparts in mer-cis-(PEt2Ph)2(PPri3)H-trans-Cl2IrIII (2) but the PPri3 ligands are differently oriented and differently configured. Metal-ligand distances [ Ir -P(1,2,3) 2.333(2), 2.404(2), 2.368(2) Ǻ; Ir-Cl (1,2) 2.388(2), 2.400(2) Ǻ] are all within c. 0.02 Ǻ of those in (2). The P-Ir -P(trans) angle is 155.3(1)°.
Process-based modelling to understand the impact of ryegrass diversity on production and leaching from grazed grass-clover dairy pastures
Authors: Snow V. O. , Smale P. N. , Dodd M. B.
Published: November 2018

Ecological studies often suggest that natural grasslands with high species diversity will grow more biomass and leach less nitrogen (N). If this diversity effect also applies to fertilised and irrigated pastures with controlled removal of herbage, it might be exploited to design pastures that can assist the dairy industry to maintain production while reducing N leaching losses. The purpose of this study was to test whether pasture mixtures with a high functional diversity in ryegrass traits will confer on the system higher water- and N-use efficiency. The hypothesis was tested using a process-based model in which pasture mixtures were created with varying levels of diversity in ryegrass traits likely to affect pasture growth. Those traits were: the winter- or summer-dominance of growth, the ability of the plant to intercept radiation at low pasture mass, and rooting depth. Pasture production, leaching and water- and N-use efficiency were simulated for management typical of a dairy pasture. We found that the performance of the diverse ryegrass–clover mixtures was more strongly associated with the performance of the individual components than with the diversity across the components. Diverse pasture mixtures may confer other benefits, e.g. pest or disease resistance and pasture persistence. The testing here was within a selection of ryegrasses, and the greater possible diversity across species may produce different effects. However, these results suggest that highly performing pastures under fertilised and irrigated grazed conditions are best constructed by selecting components that perform well individually than by deliberately introducing diversity between components.
Banding phosphorus and ammonium enhances nutrient uptake by maize via modifying root spatial distribution
Authors: Ma Qinghua , Tang Hongliang , Rengel Zed , Shen Jianbo
Published: November 2018

Localised supply of phosphorus (P) plus ammonium improves root proliferation and nutrient uptake by plants grown on calcareous soils, but how nitrogen (N) forms (ammonium and urea) and placements affect maize (Zea mays L.) root distribution and nutrient uptake is not fully understood. A soil column study was conducted with four N and P combinations including P plus urea (UP), mono-ammonium phosphate (MAP), di-ammonium phosphate (DAP) and P plus ammonium sulfate (ASP), and two fertiliser application methods (banding in the 10–25 cm layer or mixing throughout the 45-cm soil profile). Shoot N and P content increased by 11–31% and 14–37% in the treatments with banding P plus ammonium (MAP, DAP or ASP) compared with banding UP and the mixing treatments. Shoot N and P uptake rates per root dry weight or root length were higher with banding P plus ammonium than their respective mixing treatments. Banding P plus ammonium increased root-length density in the fertiliser-banded layer compared with banding UP and the mixing treatments. The results show that modifying root spatial distribution by banding P plus ammonium leads to an increase in N and P uptake rates, and consequently enhances nutrient accumulation by maize.
Optimum time of sowing for rainfed winter chickpea with one-pass mechanised row-sowing: an example for small-holder farms in north-west Bangladesh
Authors: Vance W. H. , Bell R. W. , Johansen C. , Haque M. E. , Musa A. M. , Shahidullah A. K. M. , Mia M. N. N.
Published: November 2018

The time of sowing chickpea (Cicer arietinum L.) in the High Barind Tract of north-west Bangladesh is critical to crop success. To ensure adequate emergence and subsequent crop growth, chickpea relies on residual soil moisture stored in the profile after rice (Oryza sativa L.) cultivated in the preceding rainy season. With the development of mechanised, one-pass minimum tillage sowing, the time between rice harvest and chickpea sowing is decreased, and temperature constraints that limit biomass and/or pod formation and filling may be avoided. Minimum tillage may also limit evaporation from the soil surface compared with traditional, full cultivation procedures. The objective of this study was to identify the optimum sowing time to achieve adequate crop establishment and limit exposure of the chickpea crop to terminal drought and heat stress later in the growing season. Over three experimental seasons, chickpea sowing dates were spread from 22 November to 22 December. Soil water content, crop growth and temperature were monitored to determine the optimum sowing time.
Over all seasons and sowing dates, the volumetric soil water content in the seedbed under minimum tillage remained within 17–34%, a range non-limiting for chickpea establishment in glasshouse and field experiments. Late planting (after 10 December) exposed seedlings to low temperatures (<15°C), which limited biomass formation and extended the vegetative growth phase into periods with high maximum temperatures (>35°C), resulting in unfilled pods and depressed grain yield. The preferred sowing time was determined to be 30 November to 10 December to reduce the risk of high temperatures and low soil water content during chickpea reproductive growth causing terminal heat and drought stress, respectively. Mechanised sowing in one operation allows farmers to optimise their time of sowing to match seed requirements for soil water at emergence and may assist farmers to avoid temperature stresses (both low and high) that constrain chickpea vegetative and reproductive growth.
SYBR Green I based RT-qPCR assays for the detection of RNA viruses of cereals and grasses
Authors: Dráb T. , Svobodová E. , Ripl J. , Jarošová J. , Rabenstein F. , Melcher U. , Kundu J. K.
Published: November 2018

Less prevalent viruses of family Poaceae are usually excluded from the focus of interest, even though they represent a possible threat to agricultural production. We designed and validated a set of primer pairs suitable for detection and quantification of five RNA viruses, Lolium latent virus (LoLV), Oat necrosis mottle virus (ONMV), Ryegrass mosaic virus (RgMV), Soil-borne cereal mosaic virus (SBCMV), and Spartina mottle virus (SpMV), by means of one-step RT-qPCR based on SYBR Green I. These primers were used together with primers for Brome mosaic virus (BMV) and Wheat streak mosaic virus (WSMV) described elsewhere to screen grass and cereal samples from the Czech Republic. The results revealed a high prevalence of WSMV and RgMV, which pointed to possible local epidemics. We also make the first report of LoLV presence in the Czech Republic.
Multi-physiological-trait selection indices to identify Lotus tenuis genotypes with high dry matter production under drought conditions
Authors: Inostroza Luis , Acuña Hernán , Méndez José
Published: November 2018

Physiological breeding for improving drought tolerance in perennial forage legume species has been a complex task because of the low association between single physiological traits and dry matter (DM) production under drought conditions. The combination of physiological traits in selection indices may be a more effective alternative in identifying drought-tolerant genotypes. In this work, some physiological and agronomical traits were evaluated in 100 Lotus tenuis genotypes. Traits were measured in spaced plants under irrigation and rainfed conditions during two growing seasons in Chillán, Chile. Three multi-physiological trait indices were calculated based on multiple linear regression (SI1), Euclidean distance (SI2) and descriptive statistical parameters (SI3). SI1 and SI2 were significantly correlated with DM production under rainfed conditions, with correlation coefficients of 0.61 and –0.52, respectively. On the other hand, all single physiological traits showed broad genetic variability in the L. tenuis population but a low association with DM production under drought conditions. Therefore, the multi-trait indices are a more effective tool to select drought-tolerant genotypes.
Genetic diversity of eight millet genera assessed by using molecular and morphological markers
Authors: Dvořáková Zdislava , Čepková Petra Hlásná , Viehmannová Iva , Havlíčková Lenka , Janovská Dagmar
Published: November 2018

In this study, the genetic diversity and relationships among eight millet genera were investigated by molecular and morphological data analyses. Sixty-nine millet accessions were analysed by using amplified fragment length polymorphism (AFLP) markers, and evaluated for morphological traits. Eight AFLP primer pairs were amplified successfully and 779 bands were scored for all accessions, with a high level of polymorphism detected. Nei’s genetic distance among all accessions varied from 0.0123 to 0.4246 and the Shannon’s index was estimated at 0.9708. The neighbour joining tree, using the unweighted neighbour-joining method and Dice’s dissimilarity coefficient, was constructed. The AFLP markers revealed the close relatedness between the Eragrostis and Panicum genera, whereas the greatest distance was found the Pennisetum and Echinochloa genera. Cluster analysis based on the AFLP profiles revealed that the majority of accessions of a given millet genus tend to group together. Clustering from morphological data allocated individuals into three main clusters with high variation. The genetic variability found between the analysed accessions was weakly negatively correlated (r = –0.074) with their morphological attributes. However, high molecular and morphological variability indicated that this collection includes rich and valuable plant materials for millet breeding.
Identification and validation of QTLs controlling multiple traits in sorghum
Authors: Wang Hai-Lian , Zhang Hua-Wen , Du Rui-Heng , Chen Gui-Ling , Liu Bin , Yang Yan-Bing , Qin Ling , Cheng Er-Ying , Liu Qiang , Guan Yan-An
Published: November 2018

Sweet sorghum (Sorghum bicolor L. Moench) is a promising crop for biofuel and forage production, having strong resilience to multiple stresses and being capable of thriving on marginal land. The main goals in sweet sorghum improvement are to increase biomass and sugar yield. We validated quantitative trait loci (QTLs) controlling plant height, biomass, juice weight and Brix with 181 recombinant inbred lines derived from a cross between Shihong137, a dwarf grain sorghum, and L-Tian, a tall sweet sorghum, under four environments. Seven QTLs for plant height, stem and leaf fresh weight, stem fresh weight and juice weight could be repeatedly identified across four environments. However, three of those major QTLs, qPH7-2, qSLFW9 and qSFW9, had strong epistatic effect. Many QTLs related to biomass production were co-localised with previously known height QTLs, suggesting that plant height is a major trait regulating biomass production. However, qSFW1-2, qSLFW6-1, and qSLFW6-2 were mapped to positions with no known height QTL. We also identified and validated stable qBrix2 across environments. This study provided a genetic basis for integrated approaches, including plant height, to improve sweet sorghum biomass and sugar production.
Analysis of Leptosphaeria species complex causing phoma leaf spot and stem canker of winter oilseed rape (Brassica napus) in the Czech Republic
Authors: Mazáková Jana , Urban Jan , Zouhar Miloslav , Ryšánek Pavel
Published: November 2018

In the Czech Republic, increases in the area sown with oilseed rape (Brassica napus L.) and shifts to intensive crop farming systems have contributed to increased incidence and harmfulness of phoma stem canker. This study comprised a large-scale survey of the occurrence of two closely related causal agents of the disease, Leptosphaeria maculans and L. biglobosa, in oilseed rape tissues and the country-wide distribution of each fungal species. In the 2007–11 growing seasons, 1132 leaves with phoma leaf spot symptoms were sampled; from those, 977 L. maculans-type and 477 L. biglobosa-type leaf spots were sampled and analysed by species-specific PCR without pathogen isolation. There were 1159 leaf spots confirmed as infected by Leptosphaeria spp., with 65% of 907 L. maculans-type leaf spots infected by L. maculans only and 35% co-infected by both species; and with 88% of 252 L. biglobosa-type leaf spots infected by L. biglobosa only and 12% co-infected by both species. Furthermore, 217 monopycnidial isolates were collected from selected leaf spots and identified based on pigment production during solid- and liquid-media culture and PCR assay. Most (82%) isolates originating from L. maculans-type leaf lesions were L. maculans, and most (69%) isolates collected from L. biglobosa-type leaf lesions were L. biglobosa. Co-infection by both species was found in both L. maculans-type and L. biglobosa-type leaf lesions. In 2007–12, 708 stems with phoma stem canker symptoms and 2635 plant tissues from upper stem, stem base, root collar and taproot of each stem were sampled for PCR; symptoms on the four parts of each stem were assessed before taking tissue samples. There were 1495 plant tissues confirmed as infected by Leptosphaeria spp., with the proportion of plant tissue in which only L. biglobosa DNA (62%) was amplified greater than that with only L. maculans DNA (11%) or with both L. maculans and L. biglobosa DNA (27%). Although both species were detected in leaf samples in autumn, L. biglobosa was the more frequently detected species in stem samples in summer, suggesting that L. biglobosa is the more successful in colonising oilseed rape tissues in later growth stages of the plant in the Czech Republic.
Getting back the missing men of Aotearoa: declining gender inequality in NZ life expectancy
Authors: Sandiford Peter
Published: November 2018

INTRODUCTION: Men’s health is of increasing concern to policy makers worldwide. Although women generally live significantly longer than men, the difference in life expectancy in many countries is now narrowing. AIM: To document the trend in sex differences in New Zealand (NZ) life expectancy at birth (LEB) over the last decades and to determine disease patterns which account for it. METHODS: Decomposition of sex differences in LEB by age and cause for the periods 1980–82, 1985–87, 1990–92,1995–97, 2000–02, and 2005–06, using registered deaths and model life tables. RESULTS: Sex differences in LEB increased from 1951 to peak in 1976 before narrowing again. In 2006 they reached almost exactly the level they were at 55 years earlier. Changes in relative mortality from ischaemic heart disease (IHD) and to a lesser extent accidents, respiratory disease and other circulatory causes, brought about the recent decline in gender survival disparities. IHD continues to be a significant cause of gender inequality, but cancers have now become a major component of the sex difference in LEB. DISCUSSION: NZ’s experience mirrors closely that of other developed countries in pattern, timing and the age–cause composition of the trend in gender survival disparities. Thus differences in the timing of taking up smoking, found to explain a substantial portion of the trend elsewhere, were probably also important in NZ, but improvements in medical outcomes for smokers also must have played a significant role. Primary care practitioners will continue to reduce gender survival disparities by working to ensure a high uptake of services such as screening for colorectal cancer, one of many diseases responsible for lower male life expectancy. KEYWORDS: Health status disparities; sex factors; health transition; men’s health; life expectancy; women’s health
Assessing alpha and beta diversities of benthic macroinvertebrates and their environmental drivers between watersheds with different levels of habitat transformation in Japan
Authors: Ko Chia-Ying , Iwata Tomoya , Lee Jun-Yi , Murakami Aya , Okano Junichi , Ishikawa Naoto F. , Sakai Yoichiro , Tayasu Ichiro , Itoh Masayuki , Song Uhram , Togashi Hiroyuki , Nakano Shinich , Ohte Nobuhito , Okuda Noboru
Published: November 2018

Little is known about differences in species diversity among ecological communities subject to different levels of human-caused habitat transformation and how this disturbance contributes to diversity through symbiotic dependencies with the environment in freshwater ecosystems. We estimated α and β diversities
of benthic macroinvertebrates and relationships between diversity and environmental variables in Ado River (natural) and Yasu River (intermediately disturbed) watersheds, Japan. Alpha diversity was consistently slightly higher in the natural river watershed than in the intermediately disturbed one, but the spatial distribution was not equivalent. The opposite pattern was found for β diversity. Significant differences in environmental variables existed between the two river watersheds, with especially high chlorophyll-a concentrations detected in the intermediately disturbed watershed. Alpha diversity was not correlated with specific environmental variables, whereas water temperature and chlorophyll-a concentrations were the two most significant environmental variables influencing β diversity across sites in the two watersheds. These results suggest that diversity patterns in freshwater benthic macroinvertebrates are differentially influenced by levels of human-caused habitat transformation, especially that intermediately disturbed habitats may benefit species turnover, and further understanding how they relate to environmental variables is essential for protecting local to regional diversity and can provide useful information for conservation planning to maximise biodiversity at the watershed scale.
The unusual rainbow trout sex determination gene hijacked the canonical vertebrate gonadal differentiation pathway
Authors: Bertho Sylvain , Herpin Amaury , Branthonne Adèle , Jouanno Elodie , Yano Ayaka , Nicol Barbara , Muller Thomas , Pannetier Maëlle , Pailhoux Eric , Miwa Misako , Yoshizaki Goro , Schartl Manfred , Guiguen Yann
Published: November 2018

Significance

Sex determination is one of the most fundamental but also extraordinary plastic processes in nature. Many different master sex-determining genes have been characterized in vertebrates, and most of them are known to fulfill essential functions during sexual development and thus are already tightly linked to the process that they now govern. Only one exception is currently known: the salmonid master sex-determining gene (
sdY
), which arose from the duplication of an immune-related gene. Here we show that SdY prevents female differentiation by interacting and blocking the action of a key ovarian differentiation factor. These results suggest that the evolution of unusual vertebrate master sex determination genes is strongly constrained by their ability to interact with the canonical gonadal differentiation pathway.
Staphylococcus aureuscoagulases are exploitable yet stable public goods in clinically relevant conditions
Authors: Trivedi Urvish , Madsen Jonas S. , Everett Jake , Fell Cody , Russel Jakob , Haaber Jakob , Crosby Heidi A. , Horswill Alexander R. , Burmølle Mette , Rumbaugh Kendra P. , Sørensen Søren J.
Published: November 2018

Significance

Clotting of blood is not exclusive to host physiology; pathogens are also able to generate clots as part of their life cycle. Here, we show that coagulases, enzymes responsible for bacteria-mediated clotting, can act as public goods in clinical conditions. Coagulases, secreted by producers, generate protective layers of fibrin around the bacteria, shielding them from antimicrobials and host immune factors. Remarkably, we find that this protection is also conferred onto strains that do not produce coagulases but still benefit from those made by others. Although this is a social trait, overexploitation of coagulases does not occur due to spatial segregation and population viscosity. Our study provides a social evolution perspective on the critical role of coagulases.
Structural snapshots of OxyR reveal the peroxidatic mechanism of H
2
O
2
sensing
Authors: Pedre Brandán , Young David , Charlier Daniel , Mourenza Álvaro , Rosado Leonardo Astolfi , Marcos-Pascual Laura , Wahni Khadija , Martens Edo , G. de la Rubia Alfonso , Belousov Vsevolod V. , Mateos Luis M. , Messens Joris
Published: November 2018

Hydrogen peroxide (H
2
O
2
) is a strong oxidant capable of oxidizing cysteinyl thiolates, yet only a few cysteine-containing proteins have exceptional reactivity toward H
2
O
2
. One such example is the prokaryotic transcription factor OxyR, which controls the antioxidant response in bacteria, and which specifically and rapidly reduces H
2
O
2
. In this study, we present crystallographic evidence for the H
2
O
2
-sensing mechanism and H
2
O
2
-dependent structural transition of
Corynebacterium glutamicum
OxyR by capturing the reduced and H
2
O
2
-bound structures of a serine mutant of the peroxidatic cysteine, and the full-length crystal structure of disulfide-bonded oxidized OxyR. In the H
2
O
2
-bound structure, we pinpoint the key residues for the peroxidatic reduction of H
2
O
2
, and relate this to mutational assays showing that the conserved active-site residues T107 and R278 are critical for effective H
2
O
2
reduction. Furthermore, we propose an allosteric mode of structural change, whereby a localized conformational change arising from H
2
O
2
-induced intramolecular disulfide formation drives a structural shift at the dimerization interface of OxyR, leading to overall changes in quaternary structure and an altered DNA-binding topology and affinity at the catalase promoter region. This study provides molecular insights into the overall OxyR transcription mechanism regulated by H
2
O
2
.
TRPV1 pore turret dictates distinct DkTx and capsaicin gating
Authors: Geron Matan , Kumar Rakesh , Zhou Wenchang , Faraldo-Gómez José D. , Vásquez Valeria , Priel Avi
Published: November 2018

Significance

The TRPV1 channel integrates noxious stimuli from multiple sources to evoke an appropriate pain response. However, while different stimuli evoke distinct channel activation, the underlying molecular mechanisms remain unclear. Here, we aim at elucidating the structural determinants that regulate the different TRPV1 responses to two toxins: capsaicin and double-knot toxin (DkTx). We found that the channel pore turret domain imposes two opposite effects on the responses to these toxins. While it restricts the ion conductance of the DkTx-evoked current, it stabilizes the open channel state evoked by capsaicin. Together, our results indicate that TRPV1 pore turret dictates different gating mechanisms in response to agonists acting through different binding domains.
Measurability of the epidemic reproduction number in data-driven contact networks
Authors: Liu Quan-Hui , Ajelli Marco , Aleta Alberto , Merler Stefano , Moreno Yamir , Vespignani Alessandro
Published: November 2018

Significance

The analysis of real epidemiological data has raised issues of the adequacy of the classic homogeneous modeling framework and quantities, such as the basic reproduction number in real-world situations. Based on high-quality sociodemographic data, here we generate a multiplex network describing the contact pattern of the Italian and Dutch populations. By using a microsimulation approach, we show that, for epidemics spreading on realistic contact networks, it is not possible to define a steady exponential growth phase and a basic reproduction number. We show the operational use of the instantaneous reproduction rate as a good descriptor of the transmission dynamics.
Coiled-coil 1-mediated fastening of the neck and motor domains for kinesin-3 autoinhibition
Authors: Ren Jinqi , Wang Shuang , Chen Han , Wang Wenjuan , Huo Lin , Feng Wei
Published: November 2018

In kinesin-3, the coiled-coil 1 (CC1) can sequester the preceding neck coil (NC) for autoinhibition, but the underlying mechanism is poorly understood. Here, we determined the structures of the uninhibited motor domain (MD)-NC dimer and inhibited MD-NC-CC1 monomer of kinesin-3 KIF13B. In the MD-NC-CC1 monomer, CC1 is broken into two short helices that unexpectedly interact with both the NC and the MD. Compared with the MD-NC dimer, the CC1-mediated integration of NC and MD not only blocks the NC dimer formation, but also prevents the neck linker (NL) undocking and the ADP release from the MD. Mutations of the essential residues in the interdomain interaction interface in the MD-NC-CC1 monomer restored the MD activity. Thus, CC1 fastens the neck domain and MD and inhibits both NC and NL. This CC1-mediated lockdown of the entire neck domain may represent a paradigm for kinesin autoinhibition that could be applicable to other kinesin-3 motors.
Directing the reactivity of metal hydrides for selective CO
2
reduction
Authors: Ceballos Bianca M. , Yang Jenny Y.
Published: November 2018

Significance

Electrocatalytic CO
2
reduction to fuels using renewable electricity provides an entry into sustainable carbon-neutral fuels. Most reactions require proton equivalents, but direct proton reduction to H
2
leads to low product selectivity, a significant challenge in the field. The issue of product selectivity arises from shared catalytic intermediates for both CO
2
reduction and H
2
evolution. We describe how thermodynamic relationships regarding the reactivity of H
+
and CO
2
with one of these shared intermediates, homogeneous metal hydrides, can be applied to identify catalyst candidates and conditions where H
2
evolution is suppressed in favor of highly selective CO
2
reduction. The conceptual framework is used to outline operational conditions for electrocatalytic reduction of CO
2
to formate (HCO
2
−
) by [Pt(dmpe)
2
](PF
6
)
2
with negligible H
2
production.