Effects of Phagocytosis by Rabbit Granulocytes on Macromolecular Synthesis and Degradation in Different Species of Bacteria

Abstract

Phagocytosis and killing of gram-positive Bacillus megaterium and Micrococcus lysodeikticus by granulocytes in vitro is associated with almost immediate cessation of bacterial protein synthesis. By contrast, protein synthesis by Escherichia coli continues after ingestion and killing. After preincubation of E. coli with intact granulocytes for 15 min, when 95% or more of the bacteria can no longer multiply, induction of 6-galactosidase proceeds at rates about half of control values. With disrupted granulocytes, which kill E. coli as rapidly as intact cells, the rate of induction of ,B-galactosidase does not fall until after 30 min of preincubation. We attribute the different effects of phagocytosis on the biochemical apparatus of these microorganisms to the different fates of their envelopes. Specifically labeled protein, ribonucleic acid, deoxyribonucleic acid, and lipid of all three species of bacteria and peptidoglycan of E. coli are apparently incompletely degraded during phagocytosis. However, the cell walls of M. lysodeikticus and B. megaterium undergo rapid and almost complete degradation. The resulting structural disintegration of these gram-positive microorganisms must cause extensive biochemical disorganization as well. Our evidence indicates that the E. coli envelope, on the other hand, retains sufficient structural organization to preserve integrated biochemical function for at least 1 h after the bacteria have lost the ability to multiply. on August 8, 2020 by guest http://jb.asm.org/ Downloaded from the synthesis of'-galactosidase by Escherichia coli. J. Mol. Biol. 1:165-178. 13. Patriarca. P., S. Beckerdite, and P. Elsbach. 1972. Phospholipases and phospholipid turnover in Escherichia coli spheroplasts. Biochim. Biophys. Acta 260:59:3-60(0.

Hypochlorous acid-promoted loss of metabolic energy in Escherichia coli

“…Major contributing factors could include impaired transport of the inducer, loss of regulatory nucleotides, and loss of adenylate energy reserves, the last possibility arising because EC values fall far below 0.7 under these conditions (10,41). Regardless of mechanism, the observation that HOCl inhibits P-galactosidase induction is significant because it contrasts sharply with results from studies on E. coli that had been phagocytosed by neutrophils or exposed to their granule components (6,(12)(13)(14). In these instances, the bacteria retained protein biosynthetic capabilities for periods extending far beyond cellular death.…”

“…However, there is little doubt that stimulated neutrophils produce copious quantities of HOCI (18,20,21,25,48,49), so that continued macromolecular biosynthesis by phagosome-entrapped E. coli is most remarkable. The incubation media used in the studies with neutrophils (6,(12)(13)(14) contained hydrophilic HOCl-reactive compounds (e.g., tris(hydroxymethyl)aminomethane, triethanolamine, Casamino Acids (Difco), maleate ion, and/or cycloheximide), however, which may have protected the bacteria by scavenging enzymatically generated HOCl (20,44). This protective action is illustrated in Fig.…”

Alveolar Macrophage Ingestion and Phagosome-Lysosome Fusion Defect Associated with Virus Pneumonia

“…Since a virus-induced in vivo inhibition in the intracellular processing of ingested bacteria has been documented (11,18), the results herein might be interpreted as an explanation for the phagocytic defect. Suppression of phagosome-lysosome fusion would prevent the hydrolytic lysosomal enzymes to come in contact with the ingested organism (2)(3)(4), resulting in dysfunctions of intracellular processing (17,19).…”

EARLY AND DISCRETE CHANGES IN PERMEABILITY OF ESCHERICHIA COLI AND CERTAIN OTHER GRAM-NEGATIVE BACTERIA DURING KILLING BY GRANULOCYTES

“…To exclude incorporation of labeled amino acids into granulocyte protein, eycloheximide in a concentration of 0.5 mM was added to all incubation mixtures (1). At the time intervals a Abbreviations used in this paper: IPTG, isopropyl-13-v-thiogalactopyranoside; ONP, o-nitrophenol; ONPG, o-nitrophenyl-/3-D-galactopyranoside; Sup II, supernatant fluid of acid extract of disrupted granulocytes; TEA, triethanolamine.…”