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1Author    A. M. Khan, Suman Gupta, J. C. Katiyar, M.Shamim Akhtar, V. L. Sharma, A. P. BhaduriRequires cookie*
 Title    Studies on Enteric Anthelmintics: Impact of Single Point Structural Change on the Activity Profile  
 Abstract    The impact of change only in one heteroatom in the substituent at position 5(6) of methyl benzimidazole-2-carbamates on the profile of anthelmintic activity against intestinal worms An-cylostoma ceylanicum (hookworm), Nippostrongylus brasiliensis (trichostrongylid), Syphacia obvelata (oxyurid) and Hymenolepis nana (cestode) has been studied. The observations made are likely to evoke interest for understanding the SAR in methyl benzimidazole-2-carbamates anthel-mintics at a molecular level. 
  Reference    Z. Naturforsch. 43b, 233—237 (1988); received May 20 1987 
  Published    1988 
  Keywords    Anthelmintic Activity, Intestinal Worm Benzimidazole Carbamates, Structural Change, Heteroatom 
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 TEI-XML for    default:Reihe_B/43/ZNB-1988-43b-0233.pdf 
 Identifier    ZNB-1988-43b-0233 
 Volume    43 
2Author    E. Mikuli, A. Migdał-Mikuli, I. Natkanieca, B. GradRequires cookie*
 Title    Phase Transitions and Water Dynamics of [Co(H20 ) 6](C104)2 and [Mn(H20 ) 6](BF4)2 Studied by Neutron Scattering Methods  
 Abstract    Inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) patterns, registered for [Co(H20) 6](C104)2 at 18 -270 K and for [Mn(H20) 6](BF4)2 at 18 -230 K, provided evidence that these crystals possess three solid phases in these ranges of temperatures. In both compounds the phase transition occurring at T C3 is connected with a change of the crystal structure, and that occurring at T C2 with a change in the rate of the reorientational motions of H20 ligands. 
  Reference    Z. Naturforsch. 56a, 244 (2001); received December 12 2000 
  Published    2001 
  Keywords    Hexaaquacobalt(II) chlorate(VII) and Hexaaquamanganese(II) tetrafluoroborate, Phase Transitions, Structural Changes, Water Reorientation, Neutron Scattering 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0244.pdf 
 Identifier    ZNA-2001-56a-0244 
 Volume    56 
3Author    G. Ertraud Ribitsch, Rita De Clercq, Altraud Folkhard, Z. Peter, Ip, E. R3, Josef Schurz3, JuliusC. Lauw AertcRequires cookie*
 Title    Small-Angle X-Ray and Light Scattering Studies on the Influence of M g2+ Ions on the Structure of the RNA from Bacteriophage M S 2  
 Abstract    The influence o f M g2+ ions on the secondary and tertiary structure o f the RNA from bacteriophage MS2 was investigated by sm all-angle X-ray scattering and light scattering and by sedimentation experiments. The analysis o f the outer part o f the X-ray scattering curve obtained at low temperature in the absence o f Mg2+ yielded a cross-section radius o f gyration o f 0.88 nm and a mass per unit length o f 1720 g m ol-1 nn T 1. Very similar values for these parameters, which refer to the secondary structure o f the RNA m olecule, were also derived from the X-ray scattering curves obtained in the presence o f different am ounts o f Mg2+ (0.07 to 1 ions per nucleotide). On the contrary, the inner part o f the X-ray scattering curves turned out to be highly dependent on the Mg2 + concen­ tration: the cross-section radius o f gyration and the mass per unit length, which were determined from the scattering curves at small angles as parameters related to the tertiary structure o f the RNA, amounted to 3.11 nm and 4000 g m ol-1 n m -1, respectively, in the absence o f Mg2+ and in­ creased significantly upon raising the concentration o f M g2+. The increase o f these structural parameters was found to be accom panied by a decrease o f the overall radius o f gyration (as revealed indirectly by X-ray scattering and directly by light scattering m easurem ents) and by an increase o f the sedim entation coefficient. The results from the investigations o f the RNA at low temperature clearly establish the existence o f double-stranded structures dow n to very low M g2+ concentrations as well as the occurrence o f Mg2+ induced changes o f the tertiary structure. In the absence o f Mg2+ the RNA m olecule appears to be a rodlike particle o f about 300 nm length with a lateral diameter o f about 9 to 11 nm. Upon addition o f increasing am ounts o f M g2* this extended structure tightens, eventually forming a coil-like particle. Previous X-ray scattering experiments with MS 2 RNA at ionic strength 0.1 (Zipper, Folkhard and Clauwaert, FEBS Lett. 56, 2 8 3 -2 8 7 (1975)) have already established the axial dim ensions o f such coil-like particles to be about 63, 31 and 14 nm. The results from supplementary X-ray scattering experim ents performed at higher temperatures in the absence or presence o f Mg2+ clearly reflect the loss o f secondary structure due to m elting o f the RNA. This loss is, however, less pronounced at higher concentrations o f Mg2+. 
  Reference    Z. Naturforsch. 40c, 234 (1985); received August 20/D ecem b er 14 1984 
  Published    1985 
  Keywords    RNA, Interaction with M g2+, Small-Angle X -R ay Scattering, Light Scattering, Structural Changes 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0234.pdf 
 Identifier    ZNC-1985-40c-0234 
 Volume    40