Topological isomers of human uroguanylin: interconversion between biologically active and inactive isomers

AbstractThe solution structures of the two compounds of human uroguanylin (I and II), which were generated during disulfide bond forming reaction, were found to be topological isomers by 1H-nuclear magnetic resonance spectroscopy. These isomers are interconvertible in aqueous media at rates which vary with the pH and temperature of the solution. Because compound I is active in the cGMP producing assay, but compound II is not, this interconversion may be useful for evaluating the activity of human uroguanylin both in vivo and in vitro

SYMPATHETIC BLOCKADE AFTER STELLATE GANGLION BLOCK : A CONTINUOUS RECORDING USING SKIN POTENTIAL ACTIVITY

Skin potential activities (SPA) were used to assess the degree of sympathetic blockade after stellate ganglion block (SGB). The SPA were recorded bilaterally from the palmar thenar eminences in four outpatients before and after SGB. Before the SGB, the skin potential responses (SPR) on both sides were synchronous and their amplitudes were almost the same. After SGB, the SPR amplitude on the blocked side gradually fell from 1-2 minutes. Before SGB, the skin potential levels (SPL) on both sides were parallel and the lateral difference was constant. About 1-2 minutes after SGB, the SPL on the blocked side began to fall and then reached a stationary level 5 minutes after SGB. SPA variations due to factors other than peripheral blockade can be cancelled by bilateral recording. Thus, the net SPL decrease on the blocked side compared with that on the non-blocked side was proved to be a useful index for continuous, quantitative monitoring of the sympathetic blockade by the SGB

Increased expression of phosphatidylcholine (16:0/18:1) and (16:0/18:2) in thyroid papillary cancer.

A good prognosis can be expected for most, but not all, cases of thyroid papillary cancer. Numerous molecular studies have demonstrated beneficial treatment and prognostic factors in various molecular markers. Whereas most previous reports have focused on genomics and proteomics, few have focused on lipidomics. With the advent of mass spectrometry (MS), it has become possible to identify many types of molecules, and this analytical tool has become critical in the field of omics. Recently, imaging mass spectrometry (IMS) was developed. After a simple pretreatment process, IMS can be used to examine tissue sections on glass slides with location information.Here, we conducted an IMS analysis of seven cases of thyroid papillary cancer by comparison of cancerous with normal tissues, focusing on the distribution of phospholipids. We identified that phosphatidylcholine (16:0/18:1) and (16:0/18:2) and sphingomyelin (d18:0/16:1) are significantly higher in thyroid papillary cancer than in normal thyroid tissue as determined by tandem mass (MS/MS) analysis. These distributional differences may be associated with the biological behavior of thyroid papillary cancer

Proposed model for phthoxazolin A biosynthesis.

<p>A, adenylation; ACP, acyl carrier protein; AT, acyltransferase; C, condensation; Cyp, cytochrome P450; DH, dehydratase; F, formylation; KS, ketosynthase; KS⁰, KS lacking His in the HTGTG motif; KR, ketoreductase; MT, methyltransferase; PCP, peptidyl carrier protein. The presumed inactive ACP domain of module 9 is shaded in black.</p

Characterization of the biosynthetic gene cluster for cryptic phthoxazolin A in <i>Streptomyces avermitilis</i>

<div><p>Phthoxazolin A, an oxazole-containing polyketide, has a broad spectrum of anti-oomycete activity and herbicidal activity. We recently identified phthoxazolin A as a cryptic metabolite of <i>Streptomyces avermitilis</i> that produces the important anthelmintic agent avermectin. Even though genome data of <i>S</i>. <i>avermitilis</i> is publicly available, no plausible biosynthetic gene cluster for phthoxazolin A is apparent in the sequence data. Here, we identified and characterized the phthoxazolin A (<i>ptx</i>) biosynthetic gene cluster through genome sequencing, comparative genomic analysis, and gene disruption. Sequence analysis uncovered that the putative <i>ptx</i> biosynthetic genes are laid on an extra genomic region that is not found in the public database, and 8 open reading frames in the extra genomic region could be assigned roles in the biosynthesis of the oxazole ring, triene polyketide and carbamoyl moieties. Disruption of the <i>ptxA</i> gene encoding a discrete acyltransferase resulted in a complete loss of phthoxazolin A production, confirming that the <i>trans</i>-AT type I PKS system is responsible for the phthoxazolin A biosynthesis. Based on the predicted functional domains in the <i>ptx</i> assembly line, we propose the biosynthetic pathway of phthoxazolin A.</p></div