Actinoidins A and A2: structure determination using 2D NMR methods

The structural analysis of the intact glycopeptide antibiotics, actinoidins A (1a) and A2 (1b), by two-dimensional 1H NMR is described. The location of the single chlorine at the A3 position and the sites of attachment of the four carbohydrate substituents in actinoidin A are elucidated based on correlation spectroscopy (COSY), double quantum coherence experiments (DQCE), homonuclear Hartmann-Hahn experiments (HOHAHA) and nuclear Overhauser spectroscopy (NOESY). Similar 2D correlation and NOE NMR experiments are then performed on the novel analog, actinoidin A2, to determine its structure. The structural difference between actinoidins A and A2 is shown to reside in the presence of L-rhamnose in actinoidin A2 in place of L-acosamine in actinoidin A. All questions concerning the stereo-chemistry of the chiral centers in both the heptapeptide core and the carbohydrate moieties in each of these antibiotics could be successfully addressed with the exception of Gl', the alpha-carbon on the N-terminal amino acid which is known to have the R-configuration from previous studies.

Dynamics of a hydrophobic peptide in membrane bilayers by solid-state nuclear magnetic resonance

Solid-state NMR studies of the dynamics of a synthetic hydrophobic peptide, tert-butyloxycarbonylleucylphenylalanine methyl ester (Boc-Leu-Phe-OMe), in phospholipid bilayers are described. Motionally averaged powder pattern line shapes from 2H- and 15N-labeled backbone and side-chain sites of the peptide in phospholipid bilayers demonstrate the presence of both overall and internal reorientations of substantial amplitude. The peptide motions are shown to be strongly influenced by the motions of the lipids.

Incidence of antibiotic resistance and characterization of plasmids in Campylobacter jejuni strains isolated from clinical sources in Alberta, Canada

Antibiotic susceptibilities of 382 strains of Campylobacter jejuni isolated in Alberta, Canada, in 1980 and 1981 were determined. Although none were resistant to erythromycin or gentamicin, 5.4 and 22% of strains were resistant to ampicillin in 1980 and 1981, respectively. Tetracycline resistance was noted in 6.8% of strains in 1980 and in 8.6% in 1981. Moreover, resistance to high-level tetracycline (32-128 micrograms/mL) was always mediated by a plasmid of 45-50 kilobases. Three transmissible plasmids from the Alberta strains were compared with the prototype plasmid pMAK175 by restriction enzyme analysis and some minor differences in restriction sites were noted between pMAK175 and pUA183. The two other plasmids pUA142 and pUA143 were 4 kilobases larger than pMAK175 and contained additional restriction sites. However, in all plasmids examined, the HincII and AccI fragments where the tetracycline-resistance determinant was located were shown to be conserved.

Factor VII inhibitor

Factor VII inhibitor activity was identified in a 66 year old man with probable bronchogenic carcinoma. Initial studies indicated a normal partial thromboplastin time (PTT) and a prothrombin time (PT) prolongation which increased with incubation. PT correction failed to occur with 50 per cent normal plasma in vitro and 2 U of fresh frozen plasma in vivo, indicating inhibitor activity. Specific factor assay levels fell within normal limits except for a factor VII level of 30 per cent. Subsequent evaluation with antiglobulin studies suggested an inhibitor of immunoglobulin G [IgG] origin.

Purpose in life and personal values among adult alcoholics

Ideas of purpose and meaning in life, religious or spiritual values, belief in a Higher Power, and related constructs often play an important role in traditional alcoholism rehabilitation approaches, but very few data are available. Consequently, 49 males and 8 females in a 30-day inpatient treatment program for alcoholics were given the Purpose in Life (PIL) test and Study of Values (SOV) shortly after admission to the hospital and again just before discharge. Results indicated: (1) significant increases in PIL scores; (2) no significant dissimilarities between alcoholics and normals on the SPV; and (3) significant correlations between PIL and the Aesthetic and Religious scales of the SOV on the second administration only. Results were discussed in terms of future directions for research and implications for treatment.