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A new genus of anaxyelid wood wasps from the mid-Cretaceous and the phylogeny of Anaxyelidae (Hymenoptera)

Two new species of wood wasps (Anaxyelidae), Orthosyntexis elegansgen. et sp. nov. and Orthosyntexis thantisp. nov., are described from mid-Cretaceous Kachin amber. Orthosyntexisgen. nov. exhibits characters and character combinations unique to the family, such as the combination of two mesotibial spurs, a length ratio of forewing 1Rs to 1M<1, a length to width ratio of forewing cell 1mcu ≥ 2, and the presence of 2M+Cu in the hind wing. The new species and morphological characters allow for an exploration of anaxyelid phylogeny. The phylogenetic results indicate that Anaxyelidae are monophyletic and it is suggested to classify the genera in two subfamilies, Syntexinae and Anaxyelinae, the latter including Kempendajinae and Dolichostigmatinae.

ChemInform Abstract: Sulfoxides as Chiral Complexation Agents. Conformational Enantiomer Resolution and Induced Circular Dichroism of Bilirubins.

Abstract Bilirubin-IXα, the end product of porphyrin metabolism in mammals and the neurotoxic yellow-orange pigment of jaundice, exhibits a strong tendency to fold like a book into either of two interconverting enantiomeric conformations, which are further stabilized by intramolecular hydrogen bonding. Bilirubin exhibits optical activity in R-(-)-ethylmethylsulfoxide solvent, as seen by moderately strong bisignate circular dichroism Cotton effects (Δϵmax452=+10.9,Δϵmax404=-4.5), and in dichloromethane solution in the presence of 2M R-(+)-methyl-p-tolylsulfoxide its circular dichroism spectrum (Δϵ463max=+11.2,Δϵ412max=-7.1) is comparably strong. As observed earlier for chiral recognition of bilirubin by optically active amines and serum albumins, the optically active sulfoxide acts as a chiral complexation agent to induce an asymmetric transformation of bilirubin, whose bisignate circular dichroism spectra are characteristic of an exciton splitting arising from interaction of the two component dipyrrinone chromophores.

Exploring the Scope of the 29G12 Antibody Catalyzed 1,3-Dipolar Cycloaddition Reaction

[Chemical reaction: See text] 29G12 is a murine monoclonal antibody programmed to catalyze the regio- and enantioselective 1,3-dipolar cycloaddition reaction between 4-acetamidobenzonitrile N-oxide 1a and N,N-dimethylacrylamide 2a (Toker, J. D.; Wentworth, P., Jr.; Hu, Y.; Houk, K. N.; Janda, K. D. J. Am. Chem. Soc. 2000, 122, 3244). Given the unique nature of 29G12 as a protein biocatalyst for this chemical reaction, we have investigated both the substrate specificity and mechanistic parameters of the 29G12-catalyzed process. These studies have shown that while 29G12 is specific for its dipole substrate 1a, the antibody is highly promiscuous with respect to the dipolarophiles it can process. 29G12 accepts a bulky hydrophobic dipolarophile cosubstrate, with rates of product formation up to 70-fold faster than with the original substrate 2a. In all cases, the respective isoxazoline products are produced with exquisite regio- and stereochemical control (78-98% ee). Comparison between the steady-state kinetic parameters from the 29G12-catalyzed reaction of 1a with the most efficient versus the original dipolarophile cosubstrate (2m and 2a, respectively), reveals that while the effective molarities (EM)s are almost identical (EM(2m)) 26 M; EM((2a)) 23 M), the affinity of 29G12 for the larger dipolarophile 2m is more than 1 order of magnitude higher than for 2a [Km(2m) 0.44 +/- 0.04 mM; Km(2a) 5.8 +/- 0.4 mM]. Furthermore, when 2m is the cosubstrate, the affinity of 29G12 for its dipole 1a is also greatly improved [Km(1a) 0.82 +/- 0.1 mM compared to Km(1a) 3.4 +/- 0.4 mM when 2a is the cosubstrate]. An analysis of the temperature dependence of the 29G12-catalyzed reaction between 1a and 2m reveals that catalysis is achieved via a decrease in enthalpy of activation (DeltaDeltaH 4.4 kcal mol(-1)) and involves a large increase in the entropy of activation (DeltaDeltaS 10.4 eu). The improved affinity of 29G12 for the nitrile oxide 1a in the presence of 2m, coupled with the increase in DeltaDeltaS during the 29G12-catalyzed reaction between 1a and 2m supports the notion of a structural reorganization of the active site to facilitate this antibody-catalyzed reaction.

Synthesis and Characterization of Coumarin - Trioxane - Thiourea Copolymers

4-Methyl-7-hydroxy coumarin-trioxane-thiourea (MHCTTU) copolymers were prepared by copolycondensation of 4-methyl-7-hydroxy coumarin (MHC), trioxane (T) and thiourea (TU) in the presence of 2M HCl/H2SO4 as a catalyst with different molar ratios of reacting monomers. The copolymers were characterized by elemental analysis, IR spectral and TGA studies. Number average molecular weight (Mn) of all the copolymers were determined by non-aqueous conductometry titration. The electrical conductivity of all copolymers was measured at various temperatures.

Synthesis, characterisation and thermal studies of resacetophenoneoxime-thiourea-trioxane resins

Resins have been synthesised by the condensation of resacetophenoneoxime with thiourea and trioxane in the presence of 2M HCl/H 2SO 4 as a catalyst and varying molar proportion of reactants. The resins were characterised by elemental analyses, IR spectral study, number-average molecular weights and viscosity. Thermal studies of the resins have been carried out to determine their mode of decomposition, apparent activation energy and the order of each thermal reaction.

Sulfoxides as chiral complexation agents. Conformational enantiomer resolution and induced circular dichroism of bilirubins

Bilirubin-IXα, the end product of porphyrin metabolism in mammals and the neurotoxic yellow-orange pigment of jaundice, exhibits a strong tendency to fold like a book into either of two interconverting enantiomeric conformations, which are further stabilized by intramolecular hydrogen bonding. Bilirubin exhibits optical activity in R-(-)-ethylmethylsulfoxide solvent, as seen by moderately strong bisignate circular dichroism Cotton effects (Δϵmax452=+10.9,Δϵmax404=-4.5), and in dichloromethane solution in the presence of 2M R-(+)-methyl-p-tolylsulfoxide its circular dichroism spectrum (Δϵ463max=+11.2,Δϵ412max=-7.1) is comparably strong. As observed earlier for chiral recognition of bilirubin by optically active amines and serum albumins, the optically active sulfoxide acts as a chiral complexation agent to induce an asymmetric transformation of bilirubin, whose bisignate circular dichroism spectra are characteristic of an exciton splitting arising from interaction of the two component dipyrrinone chromophores.

Stable isotopic and mineralogical studies of hydrothermal alteration at Arima Spa, Southwest Japan

The waters of Arima Spa, Southwest Japan, have high salinity ( Cl = 54 g/ kg) and high isotopic ratios ( δD = − 32, and δ 18 O = + 10%.), and issue from shallow wells drilled into altered rhyolitic pyroclastic rocks of Cretaceous age. Alteration of the host rocks occurred in two stages. The earlier regional alteration stage is characterized by the presence of 2M- and IM-type muscovite, albite, chlorite, calcite and epidote, whereas muscovite and Fe-chlorite formation at the expense of partly albitized plagioclase and altered biotite or hornblende occurred in the following hydrothermal stage. Pyrite, sphalerite, galena and siderite are present in the central part of the hydrothermal alteration zone. Oxygen and hydrogen isotopic ratios of secondary muscovite show that regional alteration proceeded under the meteoric circulation, and that the hydrothermal fluid for the second stage had chemical and stable isotopic characteristics of non-meteoric origin similar to the present-day Arima brine. The oxygen and to a lesser extent the hydrogen isotopic ratios of the muscovite rapidly decrease with increasing distance from the central zone of hydrothermal alteration. The isotopic variation is best interpreted as reflecting rapidly decreasing fluid/rock ratios with increasing distance of fluid penetration from the narrow hydrothermal alteration zone into the surrounding area. Speciation computation for the present-day brines at Arima Spa indicates that they are saturated with siderite but not with calcite at depth, in good accord with the mineralogical observations. Upon ascent the brines are diluted by HCO 3-rich shallow ground water and are saturated with respect to both siderite and calcite. The present-day Arima hydrothermal system is a remnant of the second stage hydrothermal activity.

Some genetic implications of silica and aluminosilicates in peat and coal

The inorganic content of Okefenokee peat, in the absence of a significant detrital contribution, is a function of sponge spicule, phytolith, and diatom abundance in addition to the degree of organic matter decomposition and the frequency of fires. The detrital component (quartz) dominates ash composition where it is present. No clear correlation has been observed between the inorganic content of coals examined in this study and their maceral composition. Vitrinite-rich coals have a wide range of ash yield. These observations suggest that the minerals have been introduced detritally rather than accumulated as a result of peat degradation. Quartz in the coals appears to be detrital, and the presence of 2m 1 mica indicates that there is also a detrital contribution to the clay minerals present.

Polarographic studies on the effect of thiourea on deposition of copper in the presence of 2M H 2SO 4

Results of polarographic studies on the Cu(II)-thiourea-2M H 2SO 4 and equilibria resulting in that system are presented. The formation of both anodic and cathodic waves due to the copper(I)formamidine disulphide complex adsorption, anodic-cathodic waves of thioureadisulphide and copper deposition from the [Cu(CSN 2H 4) x ] +2( x = 2–4) complex are discussed. The reduction of the adsorbed complex leads to the catalytic hydrogen evolution. The influence of depolarizers charge and that of the electrode surface on electrode processes are discussed also.