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1.
Conversion of phosphatidylglycerol to lyso(bis)phosphatidic acid by alveolar macrophages 总被引:1,自引:0,他引:1
We report here studies of the synthesis of lyso(bis)phosphatidic acid [L(b)PA] by normal and BCG-elicited rabbit alveolar macrophages. This study was prompted by our earlier observations that 1) alveolar macrophages did not synthesize L(b)PA de novo despite its abundance in these cells, 2) BCG-elicited cells contained only one-quarter the amount of L(b)PA as normal cells, and 3) the turnover of arachidonate in L(b)PA led to hydroxyeicosatetraenoic acid and leukotriene synthesis. We found that exogenous phosphatidylglycerol (PG) was specifically converted to L(b)PA by both types of cells although BCG-elicited cells had only one-quarter the synthetic capacity of normal cells. Other phospholipids were found to become cell associated but were not significantly metabolized. Both glycerol moieties and the phosphate were incorporated into the product L(b)PA. However, substitution of the ester with an alkyl linkage in position 1 blocked the conversion of PG to L(b)PA. Most of the alkylphosphatidylglycerol was converted to phosphatidylcholine and phosphatidylethanolamine. This result implied that catabolism of the acyl group in position 1 was essential for L(b)PA synthesis. Because alveolar macrophages are present in a surfactant-rich milieu, we suggest that surfactant provides a source of PG for macrophage synthesis of L(b)PA in situ. It is interesting that the surfactants from rabbits challenged with BCG have a significant decrease in PG content. 相似文献
2.
The glue protein of ribbed mussels (Geukensia demissa): a natural adhesive with some features of collagen 总被引:1,自引:0,他引:1
J. Herbert Waite Douglas C. Hansen Kathleen T. Little 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1989,159(5):517-525
Summary The Atlantic ribbed musselGeukensia (Modiolus)demissa attaches itself to the roots of cord grass and other hard objects in tidal salt marshes by spinning adhesive byssal threads. The precursor of a protein apparently present in the adhesive plaques of the threads was isolated in quantity from the foot of the mussel. The protein has an apparent molecular weight of 130000, a pI of 8.1, and contains a high proportion of Gly, Glu/Gln, Lys and 3,4-dihydroxyphenyl-l-alanine (DOPA). Sequence of tryptic peptides suggests a pattern of repeated motifs, such as: Gly-DOPA-Lys, and X-Gly-DOPA-Y-Z-Gly-DOPA/Tyr-Lys, where X is Thr or Ala in octapeptides and Gln-Thr in nonapeptides. Y is variable, but more often than not hydrophobic; and Z is frequently Pro or 4-trans-hydroxyproline (Hyp). The presence of Pro-Gly and Hyp-Gly sequences of -hydroxylysine in the protein is reminiscent of typical collagens; however, the protein is not labile to clostridial collagenase, nor does collagen cross-react with antibodies raised against the mussel protein. Unlike typical collagens, Gly probably occurs only at every 4th or 5th residue in this unusual mussel protein.Abbreviations
Anti-Gdfp
anti-G. demissa foot protein
-
Dopa
3,4-dihydroxyphenylalanine
-
CTAB
cetyltrimethylammonium bromide
-
HPLC
high performance liquid chromatography
-
PAGE
polyacrylamide gel electrophoresis
Supported by grants from the National Science Foundation (DMB 8500301) and the Office of Naval Research (N00014-86K-0717) 相似文献
3.
G L Kucera C Miller P J Sisson R W Wilcox Z Wiemer M Waite 《The Journal of biological chemistry》1988,263(26):12964-12969
The hydrolysis of thioester containing phospholipids by rat liver plasmalemma phospholipase A1 was measured in a continuous spectrophotometric assay. In this assay thioester substrates were employed which, upon hydrolysis, liberated a free thiol which was reacted with 4,4'-dithiopyridine to yield the product 4-thiopyridone that absorbs at 324 nm. Thioester substrates, prepared by chemical synthesis, were used in phospholipid and Triton X-100 micelles for kinetic analysis carried out according to the method of Hendrickson and Dennis (Hendrickson, H.S., and Dennis, E.A. (1984) J. Biol. Chem. 259, 5734-5739). Vmax, Ks, and Km values obtained for various isomers and racemic mixtures of the synthetic thioester analogs are compared with corresponding oxyester substrates. Unnatural sn-1 isomers competitively inhibited the hydrolysis of natural sn-3 isomers of phosphatidylethanolamine and phosphatidic acid. Furthermore, the sn-1 isomer of phosphatidic acid was hydrolyzed by phospholipase A1, but with lower catalytic efficiency than the sn-3 isomer. The presence of a thioester at the sn-1 position did not change the Vmax significantly, as compared to the oxyester phospholipids. When two thioesters were present on the phospholipid molecule, the Vmax was decreased significantly. A convenient synthesis of 1-monothioester analogs of phospholipids is reported. The results presented show the usefulness of the spectrophotometric assay for measuring phospholipase A1 activity as well as the influence of racemic mixtures and thioesters on the hydrolytic rate. 相似文献
4.
J D Belcher L L Rudel M Waite 《Comparative biochemistry and physiology. B, Comparative biochemistry》1985,81(1):87-96
Intact rats removed more radiolabelled triacylglycerol, cholesterol, and cholesterol ester but not phosphatidylcholine (PC) in the first 6 min than hepatectomized rats. There was no difference between intact and hepatectomized rats in the transfer of radiolabelled chylomicron lipids to other lipoproteins. Specific radioactivity measurements demonstrated a net transfer of PC (intact and hepatectomized rats) and unesterified cholesterol (intact rats only) onto both the low density lipoprotein/high density lipoprotein-1 (LDL/HDL1) and HDL2 fractions. [3H]Fatty acids were rapidly incorporated into blood cell phospholipids and into HDL and LDL cholesterol esters of both intact and hepatectomized rats. Substantial rearrangements of [3H]palmitate occurred during lipid uptake by liver. 相似文献
5.
The use of acetylated cytochrome c in detecting superoxide anion production in rabbit alveolar macrophages 总被引:3,自引:0,他引:3
V N Nasrallah P S Shirley Q Myrvik M Waite 《Journal of immunology (Baltimore, Md. : 1950)》1983,131(5):2104-2106
Polymorphonuclear phagocytes have been shown to undergo marked alteration in oxidative metabolism during phagocytosis. These alterations, collectively known as the "respiratory burst", include increased glucose oxidation through the hexose monophosphate shunt (1), increased oxygen consumption (1), and increased superoxide (O-2)3 (2) and H2O2 production (3). Similar metabolic events have also been shown to occur in the rabbit alveolar macrophage (AM). There is consistent evidence that the macrophage undergoes increased oxygen consumption (4-6) and hexose monophosphate shunt activity (4-9) upon phagocytosis. There are conflicting data, however, concerning the ability of the macrophage to produce O-2. Some studies suggest that macrophages are incapable of producing measurable amounts of O-2 upon phagocytosis (7, 10-12). Other studies, however, suggest that macrophages are indeed capable of producing substantial amounts of O-2 during phagocytosis (8, 13-15). This study was designed to resolve the discrepancies in the literature concerning O-2 production in macrophages. 相似文献
6.
7.
Some properties of phospholipases of alveolar macrophages 总被引:6,自引:0,他引:6
8.
Thomas A. Waite John D. Reeve 《Ethology : formerly Zeitschrift fur Tierpsychologie》1993,93(4):326-336
Animals that store food items in scattered sites must decide how to distribute their caches in space. Our theoretical approach is based on the assumption that such animals disperse their caches in a manner that maximizes the long-term rate of storage of recoverable (surviving) food items in the habitat. We investigate the cache-spacing behavior of theoretical scatter hoarders that encounter food sources differing in the energetic content of the items they contain. We then describe a field experiment in which gray jays (Perisoreus canadensis) were presented with both small- and large-item food sources. The jays compensated for source type by spacing larger-item caches more widely, a compensation that would tend to yield a high rate of storage of recoverable food energy over the long term and throughout the territory. Previous models do not adequately account for the observed patterns of cache dispersion. 相似文献
9.
Lychees were surveyed in Queensland, Australia and in Guangdong Province and Hainan Island China, for natural enemies of the lychee erinose mite,Aceria litchii (Keifer), one of the most serious pests of lychee in Australia. A guild of seventeen predators, including ten species of phytoseiid mites, was associated with lychee erinose in Queensland. Six other predaceous mite species and a cecidomyiid larva,Arthrocnodax sp. were also part of the complex. Despite the apparent predation of most of the seventeen species recorded in Queensland onA. litchii, the pest continues to cause major problems. In China, whereA. litchii is a relatively minor pest, nine phytoseiid species were collected in lychee orchards. The value of introducing additional predators to Australia, especially from China, is discussed. 相似文献
10.
Thelma Panaïotis Marcel Babin Tristan Biard François Carlotti Laurent Coppola Lionel Guidi Helena Hauss Lee Karp-Boss Rainer Kiko Fabien Lombard Andrew M. P. McDonnell Marc Picheral Andreas Rogge Anya M. Waite Lars Stemmann Jean-Olivier Irisson 《Global Ecology and Biogeography》2023,32(11):1991-2005