A labdane derivative from Chromolaena collina and a p-hydroxyacetophenone derivative. From Stomatanthes corumbensis

A new labdane derivative, 7α-acetoxy-trans-communic acid was isolated from Chromolaena collina. Extraction of Stomatanthes corumbensis yielded a new p-hydroxyacetophenone derivative which was identified as 4-methoxy-3- [3′-methyl-4′-angeloyloxy-but-2-en- 1′-yl ]-acetophenone.     

A guaianolide and other constituents from Lychnophora species

A new guaianolide, 11 β,13-dihydroeremanthine, together with a caryophyllene derivative and pentacyclic triterpenes, has been isolated from Lychnophora species.     

Cytotoxic immune cells with specificity for defined soluble antigens. I. Assay with antigen-coated target cells

An in vitro cytotoxic system is described, in which immune cells specific for a given soluble antigen exert a specific cytotoxic effect on target cells to which this antigen has been covalently linked. The nature of the target cell is important in this system. When antigen-coated P 815-X2 mastocytoma cells and antigen-coated chicken red blood cells were incubated for several hours in culture medium at 37 °C, the presence of membrane-bound antigen could still be demonstrated on the latter, but not on the former target cells. This might be the reason why antigen-specific target cell destruction by specific immune cells was observed only with antigen-coated chicken red blood cells as target cells. The specificity of the cytotoxic effect was controlled in each experiment in a criss-cross way by using two non cross-reacting antigens both as immunogens and for coating the target cells. Specific cytotoxicity was demonstrable with both guinea pig and mouse immune cells and with different kinds of antigens: foreign proteins, hapten-heterologous protein conjugates and hapten-autologous protein conjugates.     

连续性血液净化对小儿脓毒症患者血清抗凝血酶Ⅲ, IL-6 及D- 二聚体水 平的影响

目的:探究连续性血液净化对小儿脓毒症患者血清抗凝血酶Ⅲ、IL-6及D-二聚体水平的影响。方法:收集我院收治的小儿脓毒症患儿48例,根据随机对照表分为对照组和试验组,每组各24例。两组均实施常规对症治疗,对照组患者予以低分子肝素钙治疗,试验组试验组在对照组的基础上采用床旁血滤机进行连续性血液净化治疗。治疗结束后,对比分析两组患儿临床疗效、血凝四项、T细胞亚群、抗凝血酶Ⅲ、白介素-6、D-二聚体水平以及不良反应的发生情况。结果:治疗后,与对照组相比,试验组的临床总有效率较高(P0.05);两组血清活化部分凝血活酶时间、凝血酶原时间、凝血时间、血清白介素6及D-二聚体水平下降(P0.05),纤维蛋白原、抗凝血酶Ⅲ、CD_3~+、CD_4~+、CD_8~+、CD_4~+/CD_8~+水平升高(P0.05);与对照组相比,试验组血清活化部分凝血活酶时间、凝血酶原时间、凝血时间、血清白介素6及D-二聚体水平较低(P0.05),纤维蛋白原、抗凝血酶Ⅲ、CD_3~+、CD_4~+、CD_8~+、CD_4~+/CD_8~+水平较高(P0.05);两组组不良反应发生率相比无显著差异(P0.05)。结论:连续性血液净化对小儿脓毒症的临床疗效显著,可能与上调抗凝血酶Ⅲ,下调血清IL-6及D-二聚体水平有关。     

Mass spectrometric analysis of dimer-disrupting mutations in Plasmodium triosephosphate isomerase

Electrospray ionization mass spectrometry (ESI MS) under nanospray conditions has been used to examine the effects of mutation at two key dimer interface residues, Gln (Q) 64 and Thr (T) 75, in Plasmodium falciparum triosephosphate isomerase. Both residues participate in an intricate network of intra- and intersubunit hydrogen bonds. The gas phase distributions of dimeric and monomeric protein species have been examined for the wild type enzyme (TWT) and three mutants, Q64N, Q64E, and T75S, under a wide range of collision energies (40–160 eV). The results established the order of dimer stability as TWT > T75S > Q64E ∼ Q64N. The mutational effects on dimer stability are in good agreement with the previously reported estimates, based on the concentration dependence of enzyme activity. Additional experiments in solution, using inhibition of activity by a synthetic dimer interface peptide, further support the broad agreement between gas phase and solution studies.     

Cuauthemone sesquiterpenoids from Blumea alata

The investigation of five Blumea species afforded, in addition to known compounds, several cuauthemone derivatives, most of them being 7,11-epoxides, some thymol derivatives, an eremophilane epoxide and a himachalane diol. From Pterocaulon virgatum a further himachalane derivative was isolated. The structures were elucidated by spectroscopic methods and in part by partial synthesis.     

8β-hydroxypimar-15-en-19-oic acid from Taxodium mucronatum

A new diterpenoid has been isolated from the leaves and fruits of Taxodium mucronatum. Its structure, 8β-hydroxypimar-15-en- 19-oic acid, was established by chemical and spectroscopic means.     

Germacranolides from Gochnatia vernonioides

The aerial parts of Gochnatia vernonioides afforded, in addition to dehydrocostus lactone, zaluzanin C and desacetyllaurenobiolide angelate, 14 further sesquiterpene lactones, ten 8, 12-and three 6,12-germacranolides as well as one eudesmanolide and three bisabolene derivatives. The structures were elucidated by spectroscopic methods and by comparing the data with those of closely related compounds. 8α-Angeloyloxytaraxic acid underwent an unusual autocatalysed cyclisation while the usual Cope rearrangement was not observed.     

Synthesis and solution characterization of a porphyrin-CCK8 conjugate.

In this paper we report the synthesis and a detailed NMR solution characterization of a new CCK8 analogue and its indium(III) complex, PK-CCK8 and In-PK-CCK8. The new compounds contain a porphyrin moiety covalently bound through an amide bond to the side chain of a Lys residue introduced at the N-terminus of CCK8. A molecular dynamics simulation, based on the NMR structure of the complex between CCK8 and the N-terminal extracellular arm of the CCK(A) receptor, is also reported. Both the NMR study and the molecular dynamics simulation indicate that the porphyrin-peptide conjugate might be able to bind to the CCK(A) receptor model. The results of the molecular dynamics calculations show that the conformational features of the CCK8/CCK(A) receptor model complex and of the PK-CCK8/CCK(A) receptor-model complex are similar. This evidence supports the view that the introduction of the porphyrin-Lys moiety does not influence the mode of ligand binding to the CCK(A) receptor model. The NMR structure of PK-CCK8 in DMSO consists of a well defined pseudo-helical N-terminal region, while the C-terminal region is flexible. Moreover, the absence of NOE contacts between the porphyrin and the peptide indicates that the macrocyclic ring is directed away from the peptide region involved in the binding with the receptor.     

Disulfide engineering at the dimer interface of Lactobacillus casei thymidylate synthase: crystal structure of the T155C/E188C/C244T mutant

The crystal structure of a covalently cross-linked Lactobacillus casei thymidylate synthase has been determined at 2.8 A resolution. The sites for mutation to achieve the bis-disulfide linked dimer were identified using the disulfide modeling program MODIP. The mutant so obtained was found to be remarkably thermostable. This increase in stability has been reasoned to be entirely a consequence of the covalent gluing between the two subunits.