A heat-stable factor present in extracts of human blood leukocytes is capable of lysing young Staphylococcusaureusat pH 5.0. Lysis is character- ized by breakdown of cell-wall components as judged by electron microscopic and biochemical analysis. The leukocyte extracts can be replaced by a variety of agents known to injure cell membranes, e.g., leukocyte cationic protein histone, polymyxin B, colimycin, phospholipase A, and lysolecithin. The mechanisms by which all these agents bring about the degradation of the sta- phylococcal walls was studied. By using 4C-labeled cell walls devoid of cytoplasmic structures, it was demonstrated that none of the above-men- tioned agents had a direct lytic effect on purified cell walls. On the other hand, when any of these agents first interacted with intact staphylococci, a factor (presumably an autolysin) was generated that directly lysed the cell walls. Lysis of cell wails in the presence of intact staphylococci used as a source of autolysin was strongly inhibited by a variety of anionic poly- electrolytes such as heparine and liquoid. The possible role olayed by bacterial autolysins in the generation of microbial cell-wall comp ,nents capable of triggering chronic inflammation is discussed.
About 400 Nabatean, Greek, Latin, Hebrew-Aramaic, Coptic, Armenian, and Thamudic rock-cut inscriptions were photographed in 1970-1971 in a section of Wadi Haggag in western Sinai; 267 of them are published here. They include Nabatean and pre-Christian Greek graffiti written by Nabateans in the 2nd-3rd centuries CE, a Greek inscription of the early 4th century, and Greco-Christian, Jewish, Armenian, and perhaps early Arabic inscriptions from the 5th century and later. The discussions in the catalogue are supplemented by a survey of modern exploration in the area, observations on symbols and pilgrimages, a description of the related pottery, and indexes.
OFER BAR-YOSEF ו PHILLIPS, JAMES L.. 1977.
“Qedem 7”.
This volume summarizes the emergency surveys and excavations conducted in 1970-1976 in the Gebel Maghara section of northern Sinai, an area whose prehistory was previously virtually unknown. Primary attention is devoted to the Upper Paleolithic, Epi-Paleolithic, and Neolithic occurrences and industries. Studies on the environment (past and present), radiocarbon dating, and Middle Bronze Age I finds are also included.
The role played by bacterial lipopolysaccharides (endotoxins) (LPS) in the initiation of tissue damage during bacterial infections, is well established. It is accepted that LPS is released from the invading bacteria following autolysis, and the interaction of the solubilized LPS with tissues and body fluids lead to the initiation of the physiological, pharmacological and pathological sequelae seen after infections with Gram negative bacterial. Previous studies from our laboratories have shown that the binding of LPS to membranes of RBC is markedly enhanced by heat-labile leukocyte factors2, and that leukocyte factors are also capable of activating ‘LPS’ for binding to cell surfaces. Since the ‘activation’ of LPS caused by this factor \s inhibited by protease inhibitors, it was postulated that proteases present Hn leukocytes and in inflammatory exudates may enhance tissue damage by increasing the passive sensitization of mammalian cells by LPS to subsequent lysis in the presence of antibodies and complement.
