All eukaryotic organisms have an innate immune system characterized by germ-line encoded receptors and effector molecules, which mediate detection and clearance of microbes such as bacteria, fungi, and parasites. Vertebrate animals have, in addition to innate immune responses, evolved an adaptive immune system characterized by antibodies and T-cell receptors. Insects in general and the fruit fl...

Peptidoglycan was purified from the oral bacterium Fusobacterium nucleatum strain Fev 1, using boiling sodium dodecyl sulfate and pronase. The composition of this peptidoglycan was found to be similar to that of other gram-negative bacteria, except that it lacked diaminopimelic acid. Lanthionine, the monosulfur analog of diaminopimelic acid, was identified as the diaminodicarboxylic acid of thi...

The peptidoglycan transglycosylase of Bacillus megaterium has been purified approximately 500-fold from a crude membrane fraction. This protein is likely to be the one previously called PG-II and was assayed by its ability to reconstitute with a crude phospho-N-acetyl-muramyl-pentapeptide translocase preparation and partially purified N-acetylglucosaminyl transferase to give peptidoglycan synth...

The extent and rate of cross-linking of diaminopimelic acid in the peptidoglycan of Bacillus megaterium have been determined by a new procedure. The method is based on the reaction of nitrous acid with the unprotected amino groups of non-cross-linked diaminopimelic acid. Pulse label experiments in a mutant where diaminopimelic acid is incorporated specifically into peptidoglycan demonstrated th...

Peptidoglycan synthesis rate in nonconstricting filaments of Escherichia coli dnaX(Ts) has been studied by autoradiography of incorporated [3H]diaminopimelic acid. Analysis of autoradiograms of whole cells and sacculi showed that peptidoglycan is synthesized at a reduced rate in the nucleoid-containing parts of these filaments. The lower rate of peptidoglycan synthesis in the cell center coinci...

The abundance of lysozyme on mucosal surfaces suggests that successful colonizers must be able to evade its antimicrobial effects. Lysozyme has a muramidase activity that hydrolyzes bacterial peptidoglycan and a non-muramidase activity attributable to its function as a cationic antimicrobial peptide. Two enzymes (PgdA, a N-acetylglucosamine deacetylase, and Adr, an O-acetyl transferase) that mo...

The composition of the peptidoglycan of Bordetella pertussis and the nature of its turnover products was determined by a new combination of analytical techniques: high performance liquid chromatography of an enzymatic peptidoglycan hydrolysate and fast atom bombardment mass spectrometry and fast atom bombardment collision-activated dissociation tandem mass spectrometry. Sixteen major components...

The S-layer of Bacillus stearothermophilus PV72/p2 shows oblique lattice symmetry and is composed of identical protein subunits with a molecular weight of 97,000. The isolated S-layer subunits could bind and recrystallize into the oblique lattice on native peptidoglycan-containing sacculi which consist of peptidoglycan of the A1gamma chemotype and a secondary cell wall polymer with an estimated...

Peptidoglycan is an essential and specific component of the bacterial cell wall and therefore is an ideal recognition signature for the immune system. Peptidoglycan recognition proteins (PGRPs) are conserved from insects to mammals and able to bind PGN (non-catalytic PGRPs) and, in some cases, to efficiently degrade it (catalytic PGRPs). In Drosophila, several non-catalytic PGRPs function as se...