Establishment of hybrid-derived offspring populations in the Ohomopterus ground beetles through unidirectional hybridization

An approach to deduce the mechanism of stabilization of the hybrid-derived populations in the Ohomopterus ground beetles has been made by comparative studies on the phylogenetic trees of the mitochondrial and nuclear DNA. A phylogenetic tree based on the internal transcribed spacer (ITS) of nuclear ribosomal gene roughly reflects the relations of morphological species group, while mitochondrial NADH dehydrogenase subunit 5 (ND5) gene shows a considerable different topology on the tree; there exist several geographically-linked lineages, most of which consist of more than one species. These results suggest that the replacement of mitochondria has occurred widely in the Ohomopterus species. In most cases, hybridization is unidirectional, i.e., the species A (♂) hybridized with another species B (♀) and not vice versa, with accompanied replacement of mitochondria of A by those of B. The results also suggest that partial or complete occupation of the distribution territory by a hybrid-derived morphological species. The morphological appearance of the resultant hybrid-derivatives are recognized as that of the original species A. Emergence of a morphological new species from a hybrid-derived population has been exemplified.     

Pharmacokinetics of brain natriuretic peptide in rats.

The pharmacokinetics of rat brain natriuretic peptide (rBNP) was compared with that of alpha-rat atrial natriuretic peptide (alpha-rANP) in rats. After intravenous infusion in rats (600 pmol min-1kg-1 for 2 min), the disappearance of plasma rBNP was 4-fold slower than that of alpha-rANP. The estimated mean plasma clearance rates for rBNP and alpha-rANP were 45.9 ml min-1kg-1 and 74.4 ml min-1kg-1, respectively. The affinity of rBNP for the clearance receptor or degradation enzyme was considered to be lower than that of alpha-rANP.     

Thermodynamically stable vesicle formation from glycolipid biosurfactant sponge phase

Thermodynamically stable vesicle (L(alpha1)) formation from glycolipid biosurfactant sponge phase (L(3)) and its mechanism were investigated using a "natural" biocompatible mannosyl-erythritol lipid-A (MEL-A)/L-alpha-dilauroylphosphatidylcholine (DLPC) mixture by varying the composition. The trapping efficiency for calcein and turbidity measurements clearly indicated the existence of three regions: while the trapping efficiencies of the mixed MEL-A/DLPC assemblies at the compositions with X(DLPC)< or =0.1 or X(DLPC)> or =0.8 were almost zero, the mixed assemblies at the compositions with 0.1 or =0.8 were multilamellar vesicles (L(alpha)) with diameter from 2 to 10 microm. Meanwhile, dynamic light scattering (DLS) measurement revealed that the average size of the vesicles at the composition of X(DLPC)=0.3 was 633.2 nm, which is remarkably small compared to other compositions. Moreover, the mixed vesicle solution at the composition of X(DLPC)=0.3 was slightly bluish and turbid and kept its dispersion stability at 25 degrees C for more than 3 months, indicating the formation of a thermodynamically stable vesicle (L(alpha1)). These results exhibited the formation of a thermodynamically stable vesicle (L(alpha1)) with a high dispersibility from the MEL-A/DLPC mixture. The asymmetric distribution of MEL-A and DLPC in the two vesicle monolayers caused by the difference in geometrical structures is very likely to have changed their self-assembled structure from a sponge phase (L(3)) to a thermodynamically stable vesicle (L(alpha1)).     

Effect of 1,10-phenanthroline on the extraction and separation of lithium(I), sodium(I) and potassium(I) with thenoyltrifluoroacetone

The extraction of Li⁺ with thenoyltrifluoroacetone (Htta) in the presence of 1,10-phenanthroline (phen) has been studied in various organic solvents. The remarkable enhancement of the extraction of Li⁺, that is a synergistic effect, was observed by the addition of phen, and the high extractability of Li⁺ was attained in toluene, benzene, chlorobenzene and o-dichlorobenzene. The extraction equilibrium of Li⁺, Na⁺ and K⁺ (denoted as M⁺) in the presence or absence of phen in chlorobenzene and the adduct formation reaction in the organic phase were studied in detail. The adduct of Li⁺ was Li(tta)(phen) in the wide concentration range of phen in the organic phase, while in Na⁺ and K⁺ M(tta)(phen)₂ also exists in the high concentration region. The maximum value of the separation factor between Li⁺ and Na⁺ was observed in the present system and was larger than that in the Htta-trioctylphosphine oxide (TOPO)-benzene system reported previously.     

Substoichiometric isotope-dilution determination of sulphur after conversion to methylene blue and ion-pair extraction with dodecyl sulphate

The proposed substoichiometric determination of sulphur includes two key steps: conversion of sulphur to methylene blue and ion-pair extraction of methylene blue into chloroform with a substoichiometric amount of dodecyl sulphate. The method, combined with isotope dilution is applied to the determination of total sulphur in NBS SRM Citrus Leaves and in a seaweed sample (Laminaria religiosa Miyabe). The mean values obtained were 0.401±0.008% S (RSD 2%; n=9; certified value 0.407±0.009%) for the SRM, and 0.756±0.012% S (RSD 1.6%; n=5) for the seaweed. A sample of 0.5–1 g containing ca. 100 μg of sulphur can be analysed.     

Formation of SiH bonds on the surface of microcrystalline silicon covered with SiOx by HF treatment

Infrared absorption due to the surface chemical bonds on microcrystalline silicon (μc-Si) was investigated with recycling procedures of thermal oxygenation accompanied with dehydrogenation and HF etching. SiH bonds were reformed on the surface of μc-Si by HF etching of oxygenated μc-Si. The mechanism of the SiH bond formation was proposed. It was suggested that formation of =SiH₂,

SiH₂

_x or -SiH₃ group depended on the kind of a crystalline plane.     

Cloud point extraction equilibrium of lanthanum(III), europium(III) and lutetium(III) using di(2-ethylhexyl)phosphoric acid and Triton X-100

The cloud point extraction behaviors of lanthanoids(III) (Ln(III) = La(III), Eu(III) and Lu(III)) with and without di(2-ethylhexyl)phosphoric acid (HDEHP) using Triton X-100 were investigated. It was suggested that the extraction of Ln(III) into the surfactant-rich phase without added chelating agent was caused by the impurities contained in Triton X-100. The extraction percentage more than 91% for all Ln(III) metals was obtained using 3.0 × 10⁻⁵ mol dm⁻³ HDEHP and 2.0% (v/v) Triton X-100. From the equilibrium analysis, it was clarified that Ln(III) was extracted as Ln(DEHP)₃ into the surfactant-rich phase. The extraction constant of Ln(III) with HDEHP and 2.0% (v/v) Triton X-100 were also obtained.     

Solvent extraction of lanthanoid/III/ with 18-crown-6 from aqueous trichloroacetate solutions to 1,2-dichloroethane

Extraction behaviour of lanthanoid/III/ has been investigated by using 18-crown-6/CR/ as a neutral microcyclic ligand, trichloroacetate/TCA^–/ as an anionic counter ion, and 1,2-dichloroethane as an organic solvent. From the equilibrium studies, the extractable complex such as LnCR³⁺ was found for La/III/, Ce/III/, Pr/III/, Nd/III/, Sm/III/, and Eu/III/ and also the formation of Ln/CR/ ₂ ³⁺ complexes was suggested for Tb/III/, Tm/III/, and Lu/III/. The extractability of lanthanoid/III/ steeply decreased with increase in the atomic number. This order of extractability was a reverse trend compared with that in many other extraction systems reported so far. Very high separation factors especially among light lanthanoid/III/ were observed.     

Novel enhancement effect of a proton donor on chelate extraction: Extraction of iron(III) with acetylacetone and 3,5-dichlorophenol

Effect of 3,5-dichlorophenol (DCP) on the extraction of Fe(III) with acetylacetone (Hacac) in nonpolar organic solvents has been studied. It is found that a mixture of Hacac and DCP in heptane gives much higher extraction of Fe(III) than Hacac alone. Such novel enhancement effect is ascribable to the association of tris(acetylacetonato)iron(III) [Fe(acac)₃] with DCP in the organic phase by hydrogen bonding. Association of Hacac with DCP has also been investigated and the intrinsic extraction equilibrium of Fe(III) is analyzed by using the equilibrium concentration of free Hacac and DCP. The association complexes are found to be Fe(acac)₃ · n DCP (n=1, 2, 3) in heptane, and the overall association constants (_{ass, n}) are determined to be log _{ass, 1} = 3.41, log _{ass, 2}, = 5.97 and log _{ass, 3}, = 7.50.