Afc can adopt either the fully extended or a turn conformation

Summary We have synthesized by solution methods and fully characterized two sets of terminally protected peptides based on the tricyclic C^α,α-disubstituted glycine Afc. The conformational preferences of the Afc/Gly peptides were examined by FT-IR absorption and¹H NMR techniques, while those of the Afc/TOAC peptides were primarily investigated by using fluorescence spectroscopy. The X-ray diffraction structure of an Afc derivative was also analyzed. The body of solution and crystal-state experimental data conclusively confirms previous findings that the Afc residue may either adopt the fully extended (C₅) or a turn conformation.     

Sister chromatid exchange in lymphocytes from patients with malignant lymphoma

Summary Sister chromatid exchange (SCE) frequencies were studied in differentially stained lymphocytes from 47 patients with malignant lymphoma. Thirteen patients were untreated when studied. The mean SCE frequency [±standard error (SE)] for these patients was 12.7±0.9 per mitosis. The mean score for 40 controls was 6.1±0.3. SCE mean scores were significantly higher in the untreated patients than in the controls (P<0.001). Seven patients were treated with radiotherapy alone. They demonstrated a mean SCE frequency (8.8±0.8) significantly lower (P<0.01) than that found in untreated patients. Eleven patients received cyclophosphamide within 4 weeks prior to study. They demonstrated a mean SCE frequency (14.3±1.3) significantly higher (P<0.05) than that found in patients who had received regimens that did not contain cyclophosphamide in the prior 4 weeks (11.1±1.3) or who had been off drugs for at least 8 weeks (10.1±0.8). Our data suggest that untreated patients with malignant lymphoma have elevated SCE frequencies, which may be further increased by certain chemotherapeutic agents.     

Some immunochemical properties of pollen extracellular nuclease

The extracellular nuclease fromPinus silvestris pollen was isolated and characterized. Molecular sieving produced only one peak of nuclease with apparent molecular mass of about 30 kDaltons, while molecular mass of the enzyme as determined by means of sodium dodecyl sulphate-DNA gel electrophoresis was 25.7 kDaltons or less. The nuclease exhibited one electrophoretic molecular form only. Specific antiserum against this nuclease was prepared and the nuclease was shown to be immunochemically cross-reactive with extracellular nuclease from Pinus nigra pollen. No immunochemical relationships were observed between pine nuclease and the pollen extracellular nucleases from the angiosperm species,Nicotiana tabacum, Corylus avellana, Alnus incana andBetula pubescens. No cross-reactivity was detected by double diffusion between the pine nuclease and the extracellular proteins from vegetative spores ofEquisetum arvense.     

The Position of His-Tag in Recombinant OspC and Application of Various Adjuvants Affects the Intensity and Quality of Specific Antibody Response after Immunization of Experimental Mice

Lyme disease, Borrelia burgdorferi-caused infection, if not recognized and appropriately treated by antibiotics, may lead to chronic complications, thus stressing the need for protective vaccine development. The immune protection is mediated by phagocytic cells and by Borrelia-specific complement-activating antibodies, associated with the Th1 immune response. Surface antigen OspC is involved in Borrelia spreading through the host body. Previously we reported that recombinant histidine tagged (His-tag) OspC (rOspC) could be attached onto liposome surfaces by metallochelation. Here we report that levels of OspC-specific antibodies vary substantially depending upon whether rOspC possesses an N'' or C'' terminal His-tag. This is the case in mice immunized: (a) with rOspC proteoliposomes containing adjuvants MPLA or non-pyrogenic MDP analogue MT06; (b) with free rOspC and Montanide PET GEL A; (c) with free rOspC and alum; or (d) with adjuvant-free rOspC. Stronger responses are noted with all N''-terminal His-tag rOspC formulations. OspC-specific Th1-type antibodies predominate post-immunization with rOspC proteoliposomes formulated with MPLA or MT06 adjuvants. Further analyses confirmed that the structural features of soluble N'' and C'' terminal His-tag rOspC and respective rOspC proteoliposomes are similar including their thermal stabilities at physiological temperatures. On the other hand, a change in the position of the rOspC His-tag from N'' to C'' terminal appears to affect substantially the immunogenicity of rOspC arguably due to steric hindrance of OspC epitopes by the C'' terminal His-tag itself and not due to differences in overall conformations induced by changes in the His-tag position in rOspC variants.     

Die Anwendung der Typenmethode in der phytosoziologischen Nomenklatur

Die Anwendung der Typenmethode als Hilfsmethode der phytosoziologischen Nomenklatur wurde eingehender geklärt. Einzelne Beispiele der Festlegung richtiger Namen für einige Vegetationseinheiten wurden angeführt und die Anwendung der Typenmethode in Regeln gefasst.     

6-Methyl-5-Azacytidine-Synthesis,Conformational Properties and Biological Activity. A Comparison of Molecular Conformation with 5-Azacytidine

Abstract

The title compound was prepared by the isocyanate procedure and the tri-methylsilyl method. The measurement of ¹H NMR spectrum of 6-methyl-5-azacytidine (1) revealed a preference of γ^t (46%) rotamer around C(5′)-C(4′) bond, a predominance of N conformation of the ribose ring (K_eq 0.33) and a preference of syn conformation around the C-N glycosyl bond. An analogous measurement of 5-azacytidine has shown a preference of γ⁺ (60%) rotamer around the C(5′)-C(4′) bond, a predominance of N conformation of the ribose ring (K_eq 0.41) and a preference of anti conformation around the C-N glycosyl bond. 6-Methyl-5-azacytidine (1) inhibits the growth of bacteria E. coli to the extent of 85% at 4000 μM concentration and the growth of LoVo/L, a human colon carcinoma cell line, to the extent of 30% at 100 μM concentration but did not inhibit L1210 cells at ≤ 100 μM concentration. 6-Methyl-5-azacytidine (1) exhibited no in vitro antiviral activity at ≤ 1 μM concentration.

     

Rheological investigation on dynamic and structure of separated phases in polymer mixture–ionic surfactant ternary system

Ternary systems composed of 0.30% sodium carboxymethyl cellulose (NaCMC), 0.70% hydroxypropylmethyl cellulose (HPMC), and sodium dodecylsulfate (SDS) of various concentrations (0.00–2.00%), were investigated by oscillatory and flow shear rheometry. The investigation on binary mixtures of HPMC/SDS (0.7% HPMC, 0.00–2.00% SDS) and HPMC/NaCMC (1.00% polymer mixtures with HPMC/NaCMC mass ratio ranging from 1/0 to 0/1) was also carried out. In the examined systems, various interactions between HPMC–NaCMC, HPMC–SDS and NaCMC–(HPMC–SDS) take place. The interactions may bring about phase separation in the ternary system into HPMC–SDS complex rich phase (coacervate), and NaCMC rich phase (supernatant). The possibility of employing the interactions in the ternary system to vary structural properties of the coacervate, in terms of viscoelasticity and shear rate influence, was investigated. Rheological properties of the ternary system, as well as of the separated coacervate and the supernatant were tested. Influence of shear rate on the interactions taking place in both the binary and the ternary mixtures was examined. It was found that the applied shear rate can influence the interactions. Molecular mechanisms determining the rheological properties of the coacervate were suggested. It was found that complex intermolecular interactions in the ternary system can be employed to attain control over the structural properties of the coacervate phase.