Formation of heterocyclic C-60 derivative by gas-phase ion/molecule reaction

Ion/molecule reactions of C-60 with vinyl acetate under chemical ionization conditions have been studied here. Compared with C2H3O+ from acetone, C2H3O+ from vinyl acetate undergoes the reactions more easily, a new heterocycle between C-60 and the studied ion is formed The generation of two sigma-bonds and little angle tensile force of pentatomic ring make it more stable.

High-temperature, high-pressure extraction of metallofullerenes Gd@C-2n

A high-temperature, high-pressure extraction technique with toluene and pyridine were employed for the extraction of metallofullerenes Gd@C-2n, A series of Gd@C-2n for 2n from 70 to 96 were effectively extracted by toluene. Gd@C-74 was shown to be a new stable soluble metallofullerene species. Pyridine was found to be more useful for the extraction of Gd@C-82 and Gd-2@C-80 from empty fullerenes and other metallofullerene species.

Electrochemical identification of intermediate forms of urea denaturation of horse heart cytochrome c

The electrochemical identification of the urea denaturation of horse heart cytochrome c in bulk solution at the 4,4'-dithiodipyridine-modified gold electrode is reported. The results are similar to the three-step transitions of equilibrium studies (Myer et al., Biochemistry, 19 (1980) 199) of urea denaturation of cytochrome c in bulk solution. This method permits a clear resolution of which of the three steps of urea denaturation is electrochemically related. In addition, by analysing the effects of urea on the structural forms of cytochrome c and on the solution properties, as well as the cyclic voltammetric responses of the protein, the individual forms of the urea denaturation of cytochrome c can be understood. The results reflect the superposition of protein denaturation on the electrode surface and in solution.

C-118 from fullerenols: Formation, structure and intermolecular nC(2) transfer reactions in mass spectrometry

In fast atom bombardment, two fullerenols C-60(OH)(x) (x=13-15) and C-60(OH)(x) (x-24-26) gave rise to a group of ions centered at C-118 with intervals of 24 mass units in the high mass region. In contrast, no such ions appeared in the mass spectra of pure C-60, C-70 and other fullerene derivatives such as C-60(C6H5)(10), under the same conditions. It is proposed that the pinacol rearrangement of C-60(OH)(2), resulting from partial rupture of the polyhydroxy molecules, produces C-59 with two carbon atoms bearing an unpaired electron, and that dimerization of this reactive intermediate is responsible for the formation of the predominant product C-118. An intermolecular nC(2) transfer process is used to explain the symmetrical abundance distribution of these product ions in the spectra of fullerenols.

High-yield Synthesis and Extraction of Gd@C-2n

Endohedral metallofullerene Gd@C-2n were synthesized with high-yield using the carbon-arc discharge method of activating the Gd2O3-containing graphite anode in situ and back-burning technique. A series of Gd@C-2n for 2n from 70 to 96 were effectively extracted by toluene at high-temperature and under high-pressure condition. Gd@C-82, Gd@C-74 were considered to be fairly stable and soluble metallofullerene species.

A new zirconocene complex, [{eta(5)-C5H4-C(CH2)(5)(CH2)(2)CH(CH3)(2)}2ZrCl2]

The title compound, dichlorobis{eta(5)-[1-(3-methylbutyl)-cyclohex-1 -yl]cyclopentadienyl}zirconium(IV), [ZrCl2-(C16H25)(2)], has a pseudo-tetrahedral bent-metallocene structure in which the substituted cyclopentadienyl rings are asymmetrically bonded to the central Zr atom, due primarily to the interaction between the large substituents and the Cl atoms. The molecule has local C-2 symmetry with the substituents positioned in a trans arrangement and directed towards the lateral sectors of the bent-metallocene unit.

Convenient preparation and properties of C-60(OH)(x)

In this paper, we introduce a very convenient method to produce water soluble C-60 derivatives- fullerols by the reaction of C-60 with potassium in toluene solution, FT-IR, H-1 NMR and FABMS proved the multi-hydroxyl and C-60 cage structures of the products, The properties of unstability to light, heat, basicity of aqueous solution and the solubility in some common polar solvents were also described.

VOLTAMMETRY OF CYTOCHROME-C ENTRAPPED IN HYDROGEL MEMBRANE ON GRAPHITE ELECTRODE

The voltammetric behavior of cytochrome c entrapped in hydrogel membranes at paraffin wax-impregnated spectroscopic graphite electrodes (WISGE) was studied in this paper. A pair of well-defined peaks appeared at +70 mV (vs. Ag/AgCl). Beside these two peaks, another pair of peaks emerged at around +225 mV. Further investigations suggested that at least three states of cytochrome c existed in the membranes due to the special structure of the hydrogel. The native conformation of cytochrome c molecules was stabilized by the hydrophilic environment that was formed by the hydroxyl structure of the membranes and facilitated the cytochrome c electron transfer reaction at +70 mV. The molecules directly adsorbed on the surface of the graphite electrode were responsible for the redox peaks at around +225 mV. Whether the adsorption peaks were detectable or not was related to the thickness of membranes and the pre-retaining time before the formation of membranes.

DEHYDROGENATION OF ORGANOLANTHANIDE ALKOXIDES AND X-RAY CRYSTAL-STRUCTURE OF REACTION-PRODUCT [(C5H-5)2YB(MU-OCH=C=CH2)]2

[Cp3Yb] reacts with HOR (Cp = C5H5; R = CH2CH=CH2, CH2CH2Me) in thf (thf = tetrahydrofuran)at room temperature to give complexes [{Cp2Yb(mu-OR)}2], which are dehydrogenated to yield the new complex [{Cp2Yb(mu-OCH=C=CH2)}2] in refluxing thf solution; the X-ray crystal structure shows that the new complex is dimeric with oxygen atoms as bridging groups.

PEK-C/PPS共混体系的相容性和结晶行为

结晶-非晶高聚物共混体系的相容性和结晶行为的研究已有许多报道。本工作研究了含酞侧基聚芳醚酮(PEK-C)���聚苯硫醚(PPS)共混物的相容性和结晶行为。 PEK-C��徐州工程塑料厂产品,未作封端处理,η?p/c=0.70;PPS为日本东丽产品。两者用双螺杆挤出机在320～350℃制成共混物。仪器为Perkin-Elmer DSC-7型差示扫描量热仪,升温速率10℃/min;DDV-Ⅱ-EA���全自动动态粘弹谱仪和理学D/max-ⅡBX-射线衍射仪。

Diterpenes, sesquiterpenes, and a C-15-acetogenin from the marine red alga Laurencia mariannensis

In addition to 10 known compounds (7-16), one new brominated diterpene, 10-hydroxykahukuene B (1), two new sesquiterpenes, 9-deoxyelatol (2) and isodactyloxene A (3), one new brominated C-15-acetogenin, laurenmariallene (4), and two new naturally occurring halogenated sesquiterpenes (5 and 6) that were previously obtained as intemediates in a biomimetic synthetic study of rhodolaureol and rhodolauradiol have been isolated and identified from the organic extract of the marine red alga Laurencia mariannensis. The structures of these compounds were established by spectroscopic methods. The antibacterial and antifungal activities of new compounds 1-4 were evaluated.

Laurendecumallenes A-B and laurendecumenynes A-B, halogenated nonterpenoid C-15-Acetogenins from the marine red alga Laurencia decumbens

Four new halogenated nonterpenoid C-15-acetogenins, 4:7,6:13-bisepoxy-9,10-diol-1,12-dibromopentadeca-1,2-diene (1, laurendecumallene A), 4:7,6:12-bisepoxy-9,10-diol-1,13-dibromopentadeca-1,2-diene (2, laurendecumallene 13), (3Z)-6:10,7:13-bisepoxy-12-bromo-9-hydroperoxylpentadeca-3-en-1-yne (3, laurendecumenyne A), and (3Z)-6:10,9:13-bisepoxy-12-bromo-7-chloropentadeca-3-en-1-yne (4, laurendecumenyne 13), together with one known halogenated C-15-acetogenin elatenyne (5) were isolated and identified from the organic extract of the marine red alga Laurencia decumbens. Their structures and relative stereochemistry were established by means of spectroscopic analysis including UV, IR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and ID and 2D NMR techniques. All these metabolites were submitted for the cytotoxic assay against tumor cell line A549 (human lung adenocarcinoma), but all of them were found inactive (IC50 > 10 mu g/mL).

Halogenated Terpenes and a C-15-Acetogenin from the Marine Red Alga Laurencia saitoi

Seven parguerane diterpenes: 15-bromo-2,7,19-triacetoxyparguer-9(11)-en-16-ol (1), 15-bromo-2,7,16,19-tetraacetoxyparguer-9(11)-ene (2), 15-bromo-2,19-diacetoxyparguer-9(11)-en-7,16-diol (3), 15-bromo-2,16,19-triacetoxyparguer-9(11)-en-7-ol (4), 15bromo-2,16-diacetoxyparguer-9(11)-en-7-ol (5), 15-bromoparguer-9(11)-en-16-ol (6), 15-bromoparguer-7-en-16-ol (7), two polyether triterpenes: thyrsiferol (8) and thyrsiferyl 23-acetate (9), and one C15-acetogenin, neolaurallene (10), were isolated from a sample of marine red alga Laurencia saitoi collected off the coast of Yantai. Their structures were established by detailed NMR spectroscopic analysis and comparison with literature data.

A serpin from Chinese shrimp Fenneropenaeus chinensis is responsive to bacteria and WSSV challenge

Arthropod defence responses (e.g. prophenoloxidase (proPO) activation and Toll pathway initiation) are mediated by serine proteinase cascades and regulated by serpins in haemolymph. A serpin (Fc-serpin) cDNA was cloned from the haemocytes of Fenneropenaeus chinensis by rapid amplification of cDNA ends (RACE) PCR and haemocyte cDNA library screening. The full-length cDNA consists of 1734 bp, encoding 411 amino acids with a calculated molecular mass of 46.55 kDa and a theoretical isoelectric point of 7.70. Fc-serpin contains a typical serpin-like homologue (serine proteinase inhibitors domain). The deduced protein contains a putative signal peptide of 19 amino acids and the serpin's signature sequence ((FHCNRPFLFLI389)-F-379). Fc-serpin showed some identity with Pacifastacus leniusculus serpin (42%) and Manduca sexta serpin-6 (34%). The reactive centre loop (RCL) sequences of Fc-serpin, P leniusculus serpin, M. sexta serpin-6 and Bombyx mori serpin-2 are highly similar. An Arg at the PI position of the reactive site indicates that Fc-serpin may have inhibitory activity against prophenoloxidase activating proteinase (PAP) and clotting enzyme. Transcripts of Fc-serpin mRNA were mainly detected in haemocytes and the lymphoid organ by RT-PCR. The variation of the mRNA transcription level in haemocytes followed by artificial infection with bacteria OF white spot syndrome virus (WSSV) was quantified by SYBR Green real-time PCR analysis. Expression profiles of Fc-serpin greatly fluctuated after challenge. This work represents the first report Of a serpin in penaeid shrimp. The data provide clues that Fc-serpin might play potential roles in the innate immunity of shrimp. (C) 2008 Elsevier Ltd. All rights reserved.

The complete amino acid sequence of growth hormone and partial amino acid sequence of prolactin and somatolactin from sea perch (Lateolabrax japonicus)

Growth hormone (GH), prolactin (PRL) and somatolactin (SL) were purified simultaneously under alkaline condition (pH 9.0) from pituitary glands of sea perch (Lateolabrax japonicas) by a two-step procedure involving gel filtration on Sephadex G-100 and reverse-phase high-performance liquid chromatography (rpHPLC). At each step of purification, fractions were monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and by immunoblotting with chum salmon GH. PRL and SL antisera. The yields of sea perch GH, PRL and SL were 4.2, 1.0 and 0.28 mg/g wet tissue, respectively. The molecular weights of 19,200 and 20,370 Da were estimated by SDS-PAGE for sea perch GH and PRL, respectively. Two forms of sea perch SL were found: one (28,400 Da) is probably glycosylated, while the other one (23,200 Da) is believed to be deglycosylated. GH bioactivity was examined by an in vivo assay. Intraperitoneal injection of sea perch GH at a dose of 0.01 and 0.1 mug/g body weight at 7-day intervals resulted in a significant increase in body weight and length of juvenile rainbow trout. The complete sea-perch GH amino acid sequence of 187 residues was determined by sequencing fragments cleaved by chemicals and enzymes. Alignment of sea-perch GH with those of other fish GHs revealed that sea-perch GH is most similar to advanced marine fish, such as tuna, gilthead sea bream, yellowfin porgy, red sea bream, bonito and yellow tail with 98.4, 96.2%, 95.7%, 95.2%, 94.1% and 91% sequence identity, respectively. Sea-perch GH has low identity to Atlantic cod (76.5%), hardtail (73.3%), flounder (68.4%), chum salmon (66.3%), carp (54%) and blue shark (38%). Partial amino-acid sequences of 127 of sea-perch PRL and the N-terminal of 16 amino-acid sequence of sea-perch SL have been determined. The data show that sea-perch PRL has a slightly higher sequence identity with tilapia PRL( 73.2%) than with chum salmon PRL(70%) in this 127 amino-acid sequence. (C) 2001 Elsevier Science B.V. All rights reserved.