David H Lamb

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A 1-mg/ml amount of threonine (8.4 mM) inhibited growth and sporulation of Bacillus subtilis 168. Inhibition of sporulation was efficiently reversed by valine and less efficiently by pyruvate, arginine, glutamine, and isoleucine. Inhibition of vegetative growth was reversed by asparate and glutamate as well as by valine, arginine, or glutamine. Cells in(More)
A precipitation method using deoxycholate/HCI has been applied successfully to separate unconjugated free polysaccharide from carrier protein-bound material in meningococcal polysaccharide-diphtheria toxoid conjugate vaccines. The method effectively separated free and bound polysaccharide in conjugate vaccines prepared from Neisseria meningitidis serotypes(More)
An LC-MS/MS method for determination of the break down product of N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC) urea derivative, EDU, has been developed and validated for monitoring the residual coupling reagents. Results indicate that the method exhibits suitable specificity, sensitivity, precision, linearity and accuracy for quantification of(More)
Hydrogen peroxide has been used to cleave the native Neisseria meningiditis polysaccharide (PS) from mega-Dalton molecular weight to a smaller size (approximately 20 kDa) depolymerized polysaccharide. The polysaccharide was examined after partial peroxide depolymerization to verify the presence of the carboxyl group at position 1 and the intactness of the(More)
Protein-polysaccharide conjugate vaccines are large, complex molecules that present challenges in terms of characterization. Free solution capillary electrophoresis using alkaline (pH 9-10) borate or glycine/NaOH buffers permitted electrophoresis of diphtheria toxoid (Dt) or meningococcal polysaccharide-Dt conjugates as well-formed, relatively broad peaks.(More)
Protein-polysaccharide conjugate vaccines offer the prospect of reducing morbidity and mortality due to bacterial pneumonia and meningitis but, because of their size and heterogeneity, are often a challenge to characterize by traditional analytical methods. Vaccines consisting of Streptococcus pneumoniae, or Neisseria meningiditis polysaccharide covalently(More)