Das vollständige Manuskript dieser Zuschrift erscheint in: Angew. Chem. Suppl. 1983, 668. DOI: 10.1002/ange.198306680

Click to increase image sizeClick to decrease image size ACKNOWLEDGMENTS These investigations were supported by the Cancer Research Campaign.

We have employed single molecule fluorescence spectroscopy, using a total internal reflection geometry and wide-angle detection, to study the attachment of singly fluorescently labeled DNA to a silica surface by either a streptavidin-biotin of a covalent linkage. In both cases the DNA is highly monodispersed with no evidence for aggregation. The covalent coupling gave higher signal-to-noise than the streptavidin-biotin Linkage and was therefore studied in more detail. Two components in the photobleaching times, corresponding to different states of the tetramethyl rhodamine probe, were observed: a short and long component with populations in the ratio 6.7:1. Only rarely was interconversion between these two states detected during the 30-s observation time of the experiment. Hybridization experiments using a complementary strand of DNA labeled with a different fluorophore gave a low level of colocalized fluorescence, indicating a significant fraction of the surface attached DNA was not available for hybridization. These results are consistent with the surface attached DNA spending significant time collapsed on the surface.

In the title compound, [PtCl(NH3)(2)(C9H9NO)]NO3, the complex cation features square-planar coordination around the Pt atom, with a mean deviation of 0.0007 (5) Angstrom. The aromatic 2,5-dimethylbenzoxazole ring is planar with a mean deviation of 0.008 (8) Angstrom. The dihedral angle between these two ring planes is 71.0 (2)degrees.

The fused-ring system of the title compound, C17H24O2, limits its conformational freedom. The five-membered cyclopentane and furan rings adopt envelope conformations, the tetrahydropyranone ring a boat conformation and the cyclodecanone ring a cyclodecane boat-chair-boat conformation.

This study identifies the neuronal types of the rhesus monkey lateral entorhinal cortex (LEC) and discusses the importance of these data in the context of the connectional patterns of the LEC and the possible role of these cells in neurodegenerative diseases. These neuronal types were characterized with the aid of Golgi impregnation techniques. These characterizations were based upon their spine densities, dendritic arrays, and, where possible, axonal arborizations. The cells could be segregated into only spinous and sparsely spinous types. The most numerous spinous types were pyramidal neurons. Other spinous types included multipolar, vertical bipolar and bitufted, and vertical tripolar neurons. The sparsely spinous neuronal types consisted of multipolar, horizontal bipolar and bitufted, and neurogliaform cells. These cells were further classified with the aid of histochemical stains and immunocytochemical markers. Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry stained multipolar, bipolar, and bitufted neurons. Stain for cytochrome oxidase (CO) was found in pyramidal and nonpyramidal cell types. Immunocytochemical techniques revealed several nonpyramidal neurons that contain somatostatin (Som) or substance P (SP). This study complements previous analyses of the neuronal components described in the LEC and adds further information about the distribution of selected neurochemicals within this cortex.

ChemInformVolume 18, Issue 47 Natural Products ChemInform Abstract: Structure and Conformation of Two Coprogen-Type Siderophores: Neocoprogen I and Neocoprogen II M. B. HOSSAIN, M. B. HOSSAIN Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this authorM. A. F. JALAL, M. A. F. JALAL Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this authorB. A. BENSON, B. A. BENSON Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this authorC. L. BARNES, C. L. BARNES Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this authorD. VAN DER HELM, D. VAN DER HELM Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this author M. B. HOSSAIN, M. B. HOSSAIN Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this authorM. A. F. JALAL, M. A. F. JALAL Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this authorB. A. BENSON, B. A. BENSON Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this authorC. L. BARNES, C. L. BARNES Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this authorD. VAN DER HELM, D. VAN DER HELM Dep. Chem., Univ. Okla., Norman, OK 73019, USASearch for more papers by this author First published: November 24, 1987 https://doi.org/10.1002/chin.198747368Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume18, Issue47November 24, 1987 RelatedInformation

28 = 150° at 138K.Structure was determined by directm~~thods (G.r-1.Sheldrick, ''SHELXS-86''} and refined by block-diagonal least-squares to a final R = 0.046 for 7074 observed reflections.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal and molecular structure of the dimeric 1:1 adduct of dimethyltin(IV) dichloride with 2,6-dimethylpyridine (2,6-lutidine) N-oxide at 138 KS. W. Ng, C. L. Barnes, D. Van der Helm, and J. J. ZuckermanCite this: Organometallics 1983, 2, 5, 600–608Publication Date (Print):May 1, 1983Publication History Published online1 May 2002Published inissue 1 May 1983https://pubs.acs.org/doi/10.1021/om00077a006https://doi.org/10.1021/om00077a006research-articleACS PublicationsRequest reuse permissionsArticle Views77Altmetric-Citations19LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

AbstractThe complete manuscript of this communication appears in: Angew. Chem. Suppl. 1983, 668. DOI:10.1002/anie.198306680

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray crystal and molecular structure of the dimeric 1:1 dimethyltin(IV) dichloride adduct with diphenylcyclopropenone, (Me2SnCl2.cntdot.O:CC2Ph2)2, at 138 .+-. 2 KS. W. Ng, C. L. Barnes, M. B. Hossain, D. Van der Helm, J. J. Zuckerman, and V. G. Kumar DasCite this: J. Am. Chem. Soc. 1982, 104, 20, 5359–5364Publication Date (Print):October 1, 1982Publication History Published online1 May 2002Published inissue 1 October 1982https://pubs.acs.org/doi/10.1021/ja00384a019https://doi.org/10.1021/ja00384a019research-articleACS PublicationsRequest reuse permissionsArticle Views70Altmetric-Citations32LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

The crystal structures of the sodium salts of N 4- hydroxy-5,6-dihydrocytosine-6-sulfonate and N4-hy - droxy- 1-methyl-5,6-dihydrocytosine-6-sulfonate, prod- ucts of the reaction of the mutagens hydroxyl- amine and bisulfite with cytosine or 1-methylcytosine, have been determined from X-ray data collected on an automated diffractometer. Both compounds are in the imino form, with the N4-OH located syn to the ring N(3). This conformation would prevent such modified residues in a polynucleotide from participating in normal base pairing, a finding which has relevance to the assumed mechanism of mutations caused either by modification of nucleic acids. Both reagents have been shown to be mutagenic in microbial systems, inducing primarily guanine-cytosine to adenine-thymine base- pair transitions (Hayatsu, 1976; Budowsky, 1976). Bisulfite is known to catalyze the deamination of cytosine, yielding uracil, under mildly alkaline con- ditions in aqueous media. The mechanism of hydroxyl- amine mutagenesis is less clear, but has been proposed to involve a modified cytosine residue resembling uracil or thymine in hydrogen-bonding and base-pairing capability. A problem arises in that hydroxylamine reacts with cytosine to yield more than one product (Budowsky, 1976). Recently, Hayatsu (1977) has demonstrated a 'cooperativity' in the actions of bisulfite and hydroxyl- amine, both in vitro and in vivo. The in vitro modification of cytosine with a combination of bisulfite and hydroxylamine proceeds at a much higher rate than the reaction with either reagent alone, and yields a single major product. Hayatsu observed a concomitant increase in the mutagenicity of the combination of reagents, relative to that of either reagent alone, in a bacteriophage system. We have determined the structure of sodium N 4- hydroxy-5,6-dihydrocytosine-6-sulfon ate monohydrate (CYTOS), the product of the action of bisulfite and hydroxylamine on cytosine, and therefore the putative intermediate in the mutations caused by this com- bination of reagents. The structure of sodium N4-hydroxy - 1-methyl-5,6-dihydrocytosine-6-sulfonate tetrahydrate (MCYTOS) has also been determined and is compared with that of the derivative of the free base.