The walls of Bacillus subtilis var. niger WM, grown in a Mg2+-limited chemostat culture (carbon source glucose, dilution rate = 0.2 h-', 37 "C, pH 7) contained 45 (w/w) teichoic acid, a polymer composed of glycerol, phosphate and glucose in the molar ratio 1.00 : 1.00 : 0.88, respectively.Alkaline hydrolysis of this teichoic acid yielded I-U-b-glucosylglycerol phosphate (together with small amounts of glycerol phosphate) and 13C nuclear magnetic resonance spectra of this hydrolysis product, and its derivative after alkaline phosphatase treatment, confirmed that the monomeric unit was l-O-~-glucosylglycerol-3-phosphate. Assignment of the resonances in the spectrum of undegraded teichoic acid revealed that the polymer was a poly [(2,3)glycerol phosphate], glucosidically substituted on C-1 of glycerol with /?-glucose.The walls of Bacillus subtilis var. niger contain teichoic acid under conditions of chemostat culture where phosphorus is not the growth-limiting nutrient [l, 21. However, the precise structure of this polymer is not known with certainty and therefore, in order to study its biosynthesis, it is first necessary to determine its exact composition. Previous investigations have shown that B. subtilis var. niger produces a teichoic acid built up from glycerol, phosphate and glucose [l], but no conclusive evidence has been presented about the sequence of the monomcrs in this polymer [3]; because of the complexity of the chemical techniques generally used, we looked for a more direct and unequivocal method for the sequence determination.13C nuclear magnetic resonance (I3C NMR) has scarcely been used for structural analysis of bacterial wall polymers, although Bundle et al. [4] have shown the value of this technique in elucidating the structure of 2-acetamino-2-deoxy-~-glucose phosphate polymers from Neisseriu meningitidis and Staphylococcus lactis. However, no reports have been published, to the best of our knowledge, on the application of 13C NMR techniques to teichoic acid analysis.In this paper we describe the analysis of the structure of the monomeric units of teichoic acid from Ahhrr~iarion. NMR, nuclear magnetic resonance.B. suhtilis var. niger WM by an alkaline hydrolysis procedure [5,6], and the use of 13C NMR as an analytical tool for the determination of the sequence of the monomers in the undegraded teichoic acid. MATERIALS AND METHODS Cultivation of BacteriaBacillus subtilis var. niger WM (a spontaneously occurring mutant from B. suhtilis var. niger which forms white instead of reddish colonies on peptone agar + 1 %glucose) was cultured in a 1-1 (LH-Engineering) chemostat with the dilution rate set to a value of 0.2 h-', the pH value controlled at 7.0 and the temperature regulated at 37 "C. The MgZ+-limited medium was made up essentially as described by Evans et al. [7], except that the overall concentration of each nutrient was three-quarters of that specified. Glucose was provided as the carbon source and was added to a final concentration of 22.5 g/l. The outflow tube of the chemostat was connec...

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New side-chain-modified bleomycins (BLMs) 3a-k have been synthesized by the reaction of demethyl BLM A2 with alpha-bromoacetamides (2a-k). The structures of these BLM analogues have been established by comparison of their NMR spectra with the corresponding spectra of model thiazole derivatives. Mass spectra (FAB) of the modified BLMs are not informative, since the fragmentation patterns exhibit a loss of the modified chain moiety, presumably in the matrix. The purity of the compounds is attested by TLC and HPLC analyses. Biological evaluation of 3a-k in in vitro (survival of B16 melanoma cells) shows that the compounds are almost as effective as bleomycin. Examination of the effects of 3c, 3e, and 3f on lungs of male mice indicates that the analogues do not exhibit lower pulmonary toxicity than bleomycin.

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HANS CERFONTAIN, COR KRUK, ROEL REXWINKEL, and FRANK STUNNENBERG. Can. J. Chem. 65, 2234 (1987). This study describes a method using 170 nmr to determine the intercarbonyl dihedral angle in a homologous series of seven 1,2-diketones. It is shown that the 170 nmr shifts of the 1,2-diketones are linearly dependent on both the electron density at the oxygen atoms and the n-n * excitation energy of the 1,2-diketo chromophore. Reduction of the overlap in the .rr system of the 1,2-diketo moiety leads to a gradual upfield shift of the 170 nmr signal, due to the increase in both the T-electron density at the oxygen atoms q6 and the mean transition energy AE.HANS CERFONTAIN, COR KRUK, ROEL REXWINKEL et FRANK STUNNENBERG. Can. J. Chem. 65, 2234 (1987). Cette Ctude dCcrit une mkthode qui fait appel B la rmn du 170 pour dkterminer l'angle dikdre intercarbonyles dans un sCrie homologue de sept dicttones-1,2. On dCmontre que les deplacements des dicktones-1,2 en rmn du 170 dipendent d'une fa~on IinCaire A la fois sur la densit6 Clectronique des atomes d'oxygkne que sur l'energie d'excitation n-n* du chromophore dictto-1,2. La rtduction dans le recouvrement du systkme-.rr de la portion dicCto-!,2 conduit a un dCplacement graduel vers les hauts champs du spectre rmn du 170; ce rksultat provient d'une augmentation tant de la densit6 des Clectrons-.rr au niveau des atomes d'oxygkne (96) que de l'inergie de transition moyenne (AE).[Traduit par la revue]