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To assess the role interleukins and mitogens play in regulating immunoglobulin (Ig) gene expression via the Ig enhancer and promoter, transgenic mice carrying two different Ig gene regulatory regions were generated. One, EkCAT, contains the Ig heavy chain enhancer (E) and the light chain promoter driving the chloramphenicol acetyltransferase (CAT) gene. In the other, EkCAT, CAT is under the control of the promoter alone. E and relative activity were assessed by CAT assay. In EkCAT mice, low CAT expression was consistently found in spleen, bone marrow, mesenteric lymph node, and thymus but not in brain, lung, or kidney. In EkCAT mice, CAT expression was detectable just above background in lymphoid tissues, suggesting a basic level of tissue specificity in the absence of the enhancer. Whole spleen cell cultures prepared from the mice were treated with lymphokines and mitogens. Lipopolysaccharide (LPS), concanavilin A (Con A), interleukin 6 (IL-6), and interferon- (IFN-) increased CAT expression to varying extents in cells derived from EkCAT mice but not in spleen cells prepared from EkCAT mice. Thus, the presence of E, in addition to the promoter, is essential for the stimulation of CAT expression mediated by these factors. B cells from EkCAT mice were separated by density into populations of small and large cells. In untreated small B cells, no CAT expression was detected and only addition of LPS resulted in an increase in CAT expression. In large B cells, CAT was expressed at a low level without addition of exogenous factors. Incubation with LPS, IL-6, Con A and IFN- caused CAT expression to increase several-fold. This transgenic system provides a means to identify exogenous factors that activate Ig enhancers and promoters.This work has been submitted in partial fulfillment of the requirements for the doctoral degree from the George Washington University. 相似文献
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Heiner Birkenbeil Manfred Eckert Prof. Dr. Manfred Gersch 《Cell and tissue research》1979,200(2):285-290
Summary Fixation of prothoracic glands of Galleria mellonella with a solution containing saponin permits immunocytochemical staining of the entire gland. By this means ecdysteroids were demonstrated electron microscopically to be present in the hyaloplasm and microtubules.Supported by Sächsische Akademie der Wissenschaften zu Leipzig 相似文献
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Summary The electron microscopical investigation of Y-organs of Astacus astacus revealed that during intermoult (stage C) the cytoplasm is poorly developed and that it increases at premoult (stage D). It then shows the typical signs of steroid production, namely agranular endoplasmic reticulum and mitochondria of the tubular type. Furthermore, a larger type of mitochondria with a regular pattern of internal structure is described.Supported by Sächsische Akademie der Wissenschaften zu LeipzigWe are grateful for technical assistance to Mrs. B. Cosack und Mrs. A. Schmidt 相似文献
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Heiner Römer 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1976,109(1):101-122
1. | The reactions of tympanic nerve fibers ofLocusta migratoria were recorded by glass microelectrodes in the metathoracic ganglion. |
2. | The units were classified by frequency-, intensity-, and directional characteristics as well as by their response pattern. The response to speciesspecific song is compared with the response to song ofEphippiger ephippiger. |
3. | The physiological properties lead to a classification into three types of low-frequency neurons (characteristic frequency 3.5–4 kHz; 4kHz; 5.5–6 kHz) and one type of high-frequency neuron (12–20 kHz). This is similar to other species (Gray, 1960, Michelsen, 1971). |
4. | Intensity-coding is done by sharp rising intensity characteristics and by different absolute thresholds of the units. |
5. | There is a marked directional sensitivity with some differences between LF and HF units. In the low frequency range the tympanal organ seems to react as a pressure gradient receiver; for high frequencies another mechanism is discussed. |
6. | No filtering of species-specific song takes place at the level of the receptor cells. |
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Prof. Dr. Manfred Gersch Heiner Birkenbeil Joachim Ude 《Cell and tissue research》1975,160(3):389-397
The prothoracic glands of the last instar of Galleria mellonella undergo characteristic alterations of their cellular fine structure closely related to cellular activity. During progressive secretory activity of the gland cells there are extensive plasmalemmal infoldings and formation of a pronounced lacunar system. Mitochondria of the active cell phase are characterized by a specific increase in size and paler colour of the matrix. In contrast to the alterations, nuclei, ER and Golgi cisterns do not undergo any submicroscopic changes during the different phases of cellular activity. The relationship between the substructural phenomena and the specific phases of cellular activity are discussed. 相似文献
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