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EA Dukhanina TI Lukyanova EA Romanova V Guerriero NV Gnuchev GP Georgiev DV Yashin LP Sashchenko 《Cell cycle (Georgetown, Tex.)》2015,14(22):3635-3643
PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4+ and CD8+ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response. 相似文献
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The uptake of cholesterol from high-density lipoproteins (HDL) labeled with 125I and [3H]cholesterol was examined in cultured rat luteal cells. Luteal cells were incubated with labeled HDL, following which the metabolic fate of the apolipoproteins and cholesterol moieties of the receptor-bound HDL were examined. About 50% of the originally bound HDL apolipoproteins were released into the medium in 24 h by a temperature-dependent process while only 5% of the HDL cholesterol was released unmetabolized. Inclusion of unlabeled HDL in the chase incubation resulted in increased release of apolipoprotein-derived radioactive products without significant change in the release of unmetabolized cholesterol. 60% of the apolipoprotein-derived radioactivity could be precipitated with trichloroacetic acid; the remaining trichloroacetic acid-soluble radioactive fraction was identified as [125I]iodotyrosine. Gel filtration chromatography of the chase-released material showed that the trichloroacetic acid-precipitable products, which contained no detectable amounts of cholesterol, eluted over a range of molecular sizes (9-80 kDa). No intact HDL was retroendocytosed. About 80% of trichloroacetic acid-precipitable products could be immunoadsorbed on anti-apolipoprotein A-I antibody immobilized on CNBr-activated Sepharose, suggesting the presence of fragments containing apolipoprotein A-I. This material was also capable of reassociating with native HDL. Lysosomal inhibitors were partially effective in inhibiting the amount of trichloroacetic acid-soluble products formed. The lysosomal degradation appeared to have no role in the uptake of HDL-derived cholesterol. These studies demonstrate preferential and total uptake of HDL cholesterol by luteal cells, with concomitant degradation of the lipoprotein. 相似文献
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The mechanism of ‘down regulation’ of luteinizing hormone receptors was investigated in pseudopregnant rats using a modified
radioimmunoassay capable of measuring endogenous tissue-bound hormone. Treatment of pseudopregnant animals with a desensitizing
dose (desensitization treatment) of human chorionic gonadotropin resulted in a decrease in receptor concentration. This decrease
was prevented if the animals were treated prior to the desensitization treatment with indomethacin, an inhibitor of prostaglandin
biosynthesis, suggesting a role for prostaglandins in down regulation. The desensitization treatment resulted in a time-dependent
decrease in subsequent responsiveness of the tissue to luteinizing hormone. Basal progesterone production rate was also decreased
following desensitization. Total tissue cholesterol was found to be decreased following desensitization treatment, without
any change in the ratio of free to esterified cholesterol. Mitochondrial cholesterol was significantly reduced and pregnenolone
production by the mitochondria of desensitized corpora lutea was also markedly reduced. However, when cholesterol was added
to the mitochondria of desensitized corpora lutea, pregnenolone production was increased, reaching values almost equal to
that shown by the control mitochondria. These results show that decrease in the responsiveness following desensitization treatment
is due to, besides receptor loss, decrease in tissue cholesterol, in particular mitochondrial cholesterol. The cholesterol
side chain cleavage activity, although low, appears to be functionally intact; the low activity could be attributed to low
levels of mitochondrial cholesterol. 相似文献
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Measurements were made of the water proton relaxation rate (T?12 = R2), electron spin resonance (ESR) six-line signal of ‘free’ Mn2+, and O2-evolution activity in thylakoid membranes from pea leaves. The main results are: (1) Aging of thylakoids at 35°C causes a parallel decrease in O2-evolution activity, in R2 and in the content of bound Mn, suggesting that R2 may be related to the loosely bound Mn involved in O2 evolution. (2) Treatment of thylakoids with tetraphenylboron (TPB) at [TPB] > 2 mM produces a 2-fold increase in R2, without release of Mn2+. The titration curve exhibits three sharp end points. The first end point occurs at a of 1.25, at which the O2 evolution is completely inhibited. (3) Treatment of thylakoids with NH2OH also increases R2 by nearly 2-fold, either by the reduction of the higher oxidation states of Mn to Mn2+ and / or by exposing the Mn to solvent protons. Also, progressive release of bound Mn occurs at [NH2OH] ≥ 1 mM as shown by an increase increase in the Mn2+ ESR signal and a decrease in R2. (4) Addition of H2O2 (0.1–1.0%) to thylakoids causes an enhancement of R2 similar to that by NH2OH, but without the release of Mn2+. (5) Heat treatment of thylakoids at 40–50°C releases Mn2+ and increases R2. Conversely, pH values of 7 to 4 release Mn2+ without changing R2 while pH values of 7–9 increase R2 without releasing Mn2+. Thus, both high and low pH values as well as the heat treatment cause structural changes enhancing the relaxivity of the bound Mn or of other paramagnetic species. 相似文献
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Reduction of Selenate and Selenite to Elemental Selenium by a Pseudomonas stutzeri Isolate 总被引:2,自引:1,他引:1 下载免费PDF全文
L. Lortie W. D. Gould S. Rajan R. G. L. McCready K.-J. Cheng 《Applied microbiology》1992,58(12):4042-4044
A Pseudomonas stutzeri isolate rapidly reduced both selenite and selenate ions to elemental selenium at initial concentrations of both anions of up to 48.1 mM. Optimal selenium reduction occurred under aerobic conditions between pH 7.0 and 9.0 and at temperatures of 25 to 35°C. Reduction of both selenite and selenate was unaffected by a number of anions except for sulfite, chromate, and tungstate ions, which inhibited both growth and reduction. 相似文献
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34Fusarium graminearum Schw isolates produced 4-deoxynivalenol to form significant amounts of 4, 7 — dideoxynivalenol and lesser amounts of 4 — deoxynivalenol monoacetates on grain substratesin vitro. This is the first report on the capability a large group of naturally occurring isolates to produce 4,7-dideoxynivalenol. The average levels of 4,7-dideoxynivalenol on rice, corn, barley, and wheat as a substrate were respectively 26.8, 14.0, 12.8, and 10.5% of the level of 4-deoxynivalenol. 4, 7 — dideoxynivalenol was present in all examined naturally contaminated wheat kernel samples at levels of 1.7 to 7.9% of the level of 4-deoxynivalenol. These findings suggest that more attention should be given to the occurrence of 4,7-dideoxynivalenol in cereals. 相似文献
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