D-glucosamine propanedithioacetal, an efficient chiral auxiliary in beta-lactam chemistry.

The synthesis of some monocyclic beta-lactams (monobactams) by the Staudinger reaction using D-glucosamine propanedithioacetal as chiral auxiliary is reported. The influence of several radicals at C3, C4, and C1' (sugar moiety) as well as other structural aspects are considered in relation to the antielastase activity.     

Evaluation of decay and termite resistance of wood treated with copper in combination with boron and N′-N-(1, 8-naphthalyl) hydroxylamine (NHA-Na)

This study evaluated the relative ability of various combinations of copper sulfate with either boric acid or calcium-precipitating agent, N′-N-(1, 8-naphthalyl) hydroxylamine (NHA-Na), to inhibit fungal degradation and attack by Formosan subterranean termites (Coptotermes formosanus Shiraki). Wood specimens were treated with either 1%, 0.5%, or 0.1% concentrations of copper sulfate, boric acid, NHA-Na, copper sulfate + boric acid, or copper sulfate + NHA-Na mixtures. Treated specimens were subjected to laboratory decay-resistance tests by using petri dishes inoculated with the Basidiomycetes fungi Tyromyces palustris and Trametes versicolor for 12 weeks. Treated wood specimens were also subjected to termite-resistance tests under laboratory conditions. Increased efficacy of copper sulfate against the brown-rot fungus T. palustris was observed when either boric acid or NHA-Na was added. The most effective treatments against the fungi tested were NHA-Na only treatments at 1% and 0.5% concentration levels. Boric acid treatments were not able to protect wood against decay after leaching because of excessive leaching of boron. Similar results were obtained in termite-resistance tests in comparison with decay-resistance tests. These results indicate that the efficacy of the treatments in preventing fungal and termite attack is a function of the type of preservative.     

Analysis of the fine specificity and cross-reactivity of monoclonal anti-lipid A antibodies

We have investigated the fine specificity of anti-lipid A antibodies to identify conserved lipid A antigens. Because lipid A derived from many different Gram-negative bacteria has similar biologic activities, the conserved regions may be of particular importance for the immunostimulatory and toxic properties of lipid A. We found that five of nine antibodies bound to a wide variety of Gram-negative bacteria. All these widely cross-reactive antibodies bound to the same antigenic site within lipid A. Polymyxin B, an inhibitor of lipid A activity, bound to this site as well. The widely cross-reactive antibodies bound to native and base-hydrolyzed lipid A equally well, and also bound to the monosaccharide precursor lipid X. The less cross-reactive antibodies recognized base-hydrolyzed lipid A poorly, and did not recognize lipid X at all. Other investigators have shown that lipid X has some of the activities of lipid A in vitro and can inhibit the lethal toxicity of LPS in vivo. On the basis of this study, we suggest that lipid X contains a conserved lipid A epitope as well.     

Assay of reducing sugars in the nanomole range with 2,2'-bicinchoninate

The photometric assay of reducing sugars with 2,2'-bicinchoninate was improved and its conditions were optimized. Optical density is linear between 1 and 25 nmol sugar/sample, and the assay is not affected by borate, phosphate, or other buffer anions. The molar extinction coefficients produced by the standard procedure with the 12 most common monosaccharides occurring in carbohydrates and conjugated glycocompounds are listed.     

Antigen presentation by the BCL1 murine B cell line: in vitro stimulation by LPS

We examined the antigen-presenting capacity of BCL1 tumor cells, which are capable of differentiating in vitro with respect to immunoglobulin synthesis/secretion under the influence of LPS. In vivo passaged BCL1 cells depleted of host cell contamination either by positive selection employing panning with anti-lambda reagents, or by elimination of latex-ingesting adherent cells, are capable of MHC-restricted antigen presentation to a GAT-immune T cell line. The BCL1 cells act as antigen-presenting cells when freshly explanted, but gradual loss of this function occurs, and cells cultured for 3.5 days cannot present antigen unless LPS is included during the culture period. BCL1 cells are equivalently Ia+ after the culture period with or without LPS stimulation. Other B cell lines capable of antigen presentation appear to express this trait constitutively, and the in vivo passaged BCL1 line is therefore unique among B cell lines in having antigen-presenting cell function that can be modulated. The data suggest that freshly explanted or LPS-cultured BCL1 cells are heterogeneous with respect to antigen-presenting capacity, and the basis for this heterogeneity is being sought. BCL1 offers an opportunity to study requirements for antigen presentation by B cells.