摘要:

AbstractWe used a policlonal antiserum against GABA and demonstated GABA‐immunoreactivity (GABA‐IR) in several populations of amacrine cells in the inner nuclear layer (INL), and other cells in the inner plexiform layer (IPL) of the central and peripheral retina of the chameleon. Horizontal cells do not contain GABA‐IR and the chameleon retina is therefore an exception among non‐mammals. GABA‐IR was not seen in cell bodies in the position of photoreceptor, bipolar and interplexiform cells suggesting that GABA is not involved in synaptic transmission in the outer plexiform layer of chamele

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0049

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractMBA‐15, a marrow stromal‐derived cell line, was shown to express an estrogen receptor. This finding was confirmed byin situhybridization and receptor binding assay. An exposure to estrogen (10−12–10−6m) in a dose response manner resulted in a decrease of cell proliferation as measured by MTT assay. Cell function was measured by enzymatic activities of two osteoblastic markers, CD10/NEP and alkaline phosphatase. These enzymatic activities were elevated following the estrogen treatment. This model enabled direct evaluation of the estrogen effect on stromal osteobl

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0050

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractIt has been demonstrated that in hepatocyte nuclei the chromatin phospholipid fraction is localized near the RNA in decondensed chromatin. The aim of the present study was to see if there is any linkage between phospholipids and other nuclear components. Isolated hepatocyte nuclei and nuclear membranes were treated with deoxyribonuclease and ribonuclease. No loss of phospholipids was observed after DNA digestion, whereas 48% was lost following enzymatic RNA removal. This loss of phospholipids, localized either near the membrane or inside the nucleus, was not homogeneous for all phospholipids: phosphatidylserine and sphingomyelin being the most affected. It can be concluded that 48% of nuclear phospholipids, in particular sphingomyelin, is lost with RNA removal. This result is discussed in view of a possible role of phospholipids in DNA synthesis and RNA transcription.

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0051

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractHigh level expression of the major auxin‐binding protein (ABP1) from maize (Zea maysL.) has been used to demonstrate that the machinery for retaining proteins in the endoplasmic reticulum (ER) of insect cells functions efficiently throughout the baculovirus infection cycle. Immuno‐localization showed wild‐type ABP1 (ABP1‐KDEL) to be targeted to the lumen of the ER, in accordance with its signal peptide and carboxyterminal KDEL ER‐retention signal. The protein accumulated in dilations of the ER, and none was detected at the cell surface. Immunoblotting of concentrated culture medium confirmed that ABP1‐KDEL was not secreted at a detectable level. In contrast, when the carboxyterminus was mutated to KEQL, secretion of the baculovirus‐expressed protein was readily detected. Immunolocalization and immunoblotting demonstrated that a high proportion of the ABP1‐KEQL protein was secreted at the cell surface and into the culture medium. The data demonstrate that the ER of insect cells has a great capacity to retain proteins and that this property is largely unaffected by the cellular disruption caused by baculovi

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0052

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractWe previously proposed that an enzymatic cooperation between Kupffer cells and hepatocytes may play an important role in cysteinyl leukotriene (LT) production in rat liver. Anin vitrotranscellular synthesis cysteinyl LTs by a Kupffer cell—hepatocyte coculture system was characterized here. Kupffer cells alone, with A23187 stimulation, did not generate cysteinyl LTs until supplemented either with isolated hepatocytes or with LTC4synthase and glutathione, indicating that Kupffer cells can synthesize LTA4but not convert it into LTC4. In contrast, hepatocytes converted the LTA4into cysteinyl LTs and further degraded the cysteinyl LTs. Cysteinyl LT production by the Kupffer cell—hapatocyte coculture system was optimized by addition of 1–3% serum albumin to the culture and by bringing the cell—cell distance closer to less than 3μ. Tumour necrosis factor also stimulated cysteinyl LT production by the coculture system. From these results, it is expected that the Kupffer cell—hepatocyte transcellular system for cysteinyl LT production actually functi

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0053

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractResting and active states of cells are described in terms of the expectation, derived from experiments with aqueous polymers, that they contain two modified forms of water: high density, reactive, fluid water and low density, inert, viscous water. Low density water predominates in a resting cell and is converted to high density water in an active cell. It is proposed that switching from one state to another is an integral part of cellular function. When this ability is lost cells are transformed either to a state of rigor or to a hyperactive state in which they no longer depend upon external signals.

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0054

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractCells ofTetrahymenamay produce autocrine signal molecules with effects on survival and proliferation. Here we have tested the effects of human recombinant and bovine insulin, and the B22–B30 fragment of bovine insulin over a wide range of concentrations (10−5–10−18m) on cell survival and proliferation in a synthetic nutrient medium. The cells were grown in conical flasks at low initial cell densities (40 and 400cells/ml). Insulin prevented rapid cell death and/or promoted cell proliferation over two separate concentration ranges: down to nanomolar levels and again in the low pico‐ and femtomolar range. At an initial population density of 400cells/ml the cells multiplied at both concentration intervals. At 40 or fewer organisms/ml the cells multiplied in the high concentration interval, whereas in the low interval they survived for about four times longer than those in the control cultures. B22–B30 added to cultures of 40 initial cells/ml produced a stimulation of cell survival in the low pico‐ and high femtomolar range. In the presence of hemin (50nm) cells at 400 initial organisms/ml multiplied at insulin concentrations down to about 3nmand again from 300amto 10pm. In some cases, hemin plus insulin activated cell proliferation between the two concentration intervals as well. At 40cells/ml the cells not only survived but proliferated in the femtomolar range. Cells in cultures supplemented with both hemin and B22–B30 multiplied at the low concentration interval (from abou

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0055

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractMouse fibroblasts (B‐6) were cultured on agar‐coated dishes. After cells grew for 2–3 generations relatively rapidly in suspension, they began to grow very slowly (stationary phase). Electron microscopic studies showed that cells in a stationary phase developed intracellular organella: membranous structures (endoplasmic reticulum and Golgi apparatus) became manifest and the number of mitochondria increased. The specific activities of succinic‐cytochrome c reductase and 5′‐nucleotidase were three and five times higher, respectively, than those of cells

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0056

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0057

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0058

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY