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1.
Autoradiography and scintillation counting have been used for evaluation of lymphocyte turnover and life span in the bone marrow, peripheral blood and thoracic duct lymph of BALB/C mice. It was shown that the bone marrow contained two populations of small lymphocytes. One population was labelled 100% after 3–4 days of intensive injections of 3H-thymidine and constituted about 75% of the lymphocytes. The remaining 25% of the lymphocytes turned over at a much slower rate comparable to the rate of increase in labelled small lymphocytes of the thoracic duct. More than 10% of the small lymphocytes of the bone marrow were found to be unlabelled after 10 days of intensive injections of 3H-thymidine. Nine weeks after giving 3H-thymidine for 30 consecutive days, 8·6% of the small lymphocytes in the bone marrow remained labelled. The mean grain counts of cells in this population were comparable to those of thoracic duct lymphocytes at corresponding times. About 90% of the peripheral blood lymphocytes were found to have a slow turnover and a long life span.  相似文献   

2.
THE TEMPO OF LYMPHOCYTE RECIRCULATION FROM BLOOD TO LYMPH IN THE RAT   总被引:7,自引:0,他引:7  
Radioactively labelled thoracic duct lymphocytes were obtained either by incubation in vitro with 3H-uridine or 14C-uridine or by giving potential donors repeated injections of 3H-thymidine finishing 17 days before thoracic duct cannulation. These labelled TDL were injected i.v. into syngeneic recipients which had been subjected to splenectomy and thoracic duct cannulation on the previous day. The tempo of lymphocyte recirculation from blood to lymph was reflected by the time at which radioactivity was recovered in the thoracic duct lymphocyte output of the recipient. This was measured by scintillation counting of 2-hourly fractional collections for 36 hr after the injection. Two lines of evidence showed that the majority of small lymphocytes which label intensely with radioactive uridine in vitro were uniform in their 'migration potential'with a modal blood to lymph transit time of 14–18 hr. By contrast the cells which were labelled in vivo with 3H-thymidine included a slower population with a modal transit time of 24–28 hr. These conclusions can be more fully interpreted in the light of recent evidence on thymic-independent ('B') lymphocytes.  相似文献   

3.
Abstract Oral immunization of suckling mice with Cryptosporidium parvum results in a humoral response to a limited set of antigens. Six-day-old BALB/c mice were each inoculated orally with 1 × 106 viable oocysts and subsequently administered oral inoculations of 2 × 106 viable oocysts at 30 and 60 days following the primary infection. After 45 days, mice were boosted with 1 × 106 oocysts orally, plus soluble extracts equivalent to 2 × 106 and 1 × 106 oocysts given intravenously and intraperitoneally, respectively. Four days later, splenic lymphocytes were fused to Ag8 myeloma cells. Using this method, we have been able to select for monoclonal antibodies that predominately recognize sporozoite surface and apical complex antigens.  相似文献   

4.
Objectives: To explore proliferation of glomerular mesangial cells (GMC) and secretion of extracelluar matrix (fibronectin induced by sublytic C5b-9 complexes), and then ascertain the role of phosphatidylinositol 3-kinase (PI3-k)/Akt signal pathway in these processes, by using small hairpin RNAs.
Material and methods: The expression of cyclin D2, 3H-thymidine into DNA and production of fibronectin including thrombospondin-1 and transforming growth factor-β1 in the GMCs stimulated by sublytic C5b-9 or transfected with expression vectors of PI3-k and Akt short hairpin RNA or LY294002 (PI3-k inhibitor) were measured by Real-time quantitative polymerase chain reaction (PCR), Western blot, enzyme-linked immunosorbent assay (ELISA) and 3H-thymidine incorporation (3H-TdR), respectively.
Results: The expression of cyclin D2, 3H-thymidine into DNA and fibronectin in the GMCs stimulated by sublytic C5b-9 could all be increased, and the elevations of these parameters mentioned above were also markedly reduced in the GMCs transfected with vectors of PI3-k and Akt short hairpin RNA or LY294002, respectively.
Conclusions: These data indicate that sublytic C5b-9 can promote proliferation of GMCs and secretion of fibronectin as well as synthesis of thrombospondin-1 and transforming growth factor-β1. The PI3-k/Akt signal pathway in these reactions, mediated by sublytic C5b-9 complexes, may play at least a partial role.  相似文献   

5.
Gldfish, Carassius auratus of varying sizes were conditioned in continuous light or darkness f or 10, 20 and 30 days and the incorporation of 3H-thymidine into the gonads was investigated to attempt to develop a bioassay for fish gonadotropins.
The 24-hour gonadal 3H-thymidine of 10-day conditioned fish was significantly less at the dose level of 0.5 μCi 3H-thymidine/fish compared to 1.0, 2.0 and 3.0 μCi/fish which gave gonadal activities not significantly different from each other. Thus, for all subsequent work the dose of 1.0 μCi/fish was used.
Photoperiod of continuous light or darkness had little effect on fish weighing less than 11 g but in fish 11-15 g conditioned for 20 days in darkness and fish greater than 16 g conditioned for 10 days in darkness, depression in gonadal 3H-thymidine incorporation occurred. In fish 11-15 g, prolonged conditioning for 30 days in darkness induced more gonadal activity than was observed at 20 days.
The effect of injection of Channa striatus pituitary extract at doses of 1 mg/10 g body weight and 5 mg/10 g body weight induced a significant increase in 3H-thymidine incorporation in the gonads over saline injected controls. The results suggest the potential of using photoperiod as a means of inducing regression of gonads of suitable fish in a bioassay of gonadotropins.  相似文献   

6.
1. Production of heterotrophic bacterioplankton was estimated monthly by the tritiated thymidine and leucine incorporation methods during the draining and filling of the mesotrophic Lake Pareloup (over a 2.5-years sampling program).
2. Rates of 3H-leucine (leu) and 3H-thymidine (thy DNA) incorporation generally paralleled each other but the ratio of leu/thy DNA incorporation rates was higher for the draining period (34.5 mean) than during and after filling (11.5 mean).
3. After draining, the highest ratios were observed during periods of low temperature and low bacterial specific activity, while DNA labeling by 3H-thymidine was reduced. However, bacterial production estimates obtained by 3H-leucine (BPL) and 3H-thymidine (BPT) incorporation methods were generally well correlated and the average BPL/BPT ratio was equal to 0.78.
4. In addition, both methods were applied during a diel cycle in three lakes of different trophic status. An increase of leu/thy DNA incorporation rates was noted from the oligotrophic to the eutrophic system. In the absence of Cyanobacteria, BPL and BPT values were quite concordant on average.
5. In situations of unbalanced growth, BPL and BPT values can diverge but when considered over a sufficient period of time they were found to be in agreement.  相似文献   

7.
The embryos, kept at 20°C for 3 hr–6 hr from the time of fertilization (at the morula stage), were cultured in sea water containing cycloheximide (10–16 mM) for successive 3 hr and then transferred to normal sea water. The embryos, thus treated, became vegetalized larvae. With the same treatment performed at a developmental stage prior to 3 hr of fertilization, most of embryos developed to small blastulae filled with mesenchyme-like cells. The treatment at a stage after 6 hr of fertilization yielded normal plutei. From the embryos exposed to both 14C-leucine and 3H-thymidine during the treatment, labelled chromatin was isolated. Only in the presumptive vegetalized embryos obtained by the cycloheximide treatment of morulae, ratio of 14C-radioactivity found in proteins of chromatin to 3H-radioactivity in DNA was markedly lower than that observed in chromatin from control embryos. The rate of 3H-radioactivity-decrease by DNase I treatment was higher in chromatin isolated from the presumptive regetalized embryos than that observed in chromatin isolated from control ones. Probable failure of chromatin structure formation, due to cycloheximide-inhibition of chromatin protein synthesis, seems to disturb the determination in the embryos at the morula stage, resulting in an induction of vegetalized embryos.  相似文献   

8.
Abstract The biosynthesis of DNA, RNA, proteins and lipids in the presence of antiserum to sulfolipids was investigated by studying the incorporation of radiolabelled precursors like 3H-thymidine 14C-uracil, 14C-leucine and 14C-Acetate into their respective macromolecules. Antiserum to sulfolipids had a inhibitory effect on the biosynthesis of all these components. Antiserum also exhibited a growth inhibitory effects as compared to normal serum.  相似文献   

9.
Abstract: Following incubation with [14C]y-aminobutyric acid (GABA) or [3H]dopamine, slices of rat striatum were superfused with media containing 36 mM K+ or ethylenediamine (EDA), 1 or 5 mM. Both K+ and EDA induced a release of [14C]GABA, the K+-induced release being largely Ca2+-dependent, while the EDA-induced release was not. Whereas K+ also evoked a Ca2+-dependent release of [3H]dopamine, EDA evoked no release of dopamine. EDA may therefore have potential as a specific GABA releasing agent.  相似文献   

10.
The granulocytic chalone is secreted by mature granulocytes and inhibits 3H-thymidine incorporation of proliferating granulocytes in vitro . The effect and the cell line specificity of this chalone was assessed with the in vivo diffusion chamber culture technique. Tests were carried out on cultures from normal mouse bone marrow cells and mouse and rat blood leucocytes. The majority of the DNA synthesizing cells in marrow cultures were proliferating granulocytes. Macrophages and immunoblasts proliferated in rat leucocyte cultures, when the chambers had been carried for 5 days in host mice. Repeated chalone or control injections were given i.p. to the host mice during 6–7 hr prior to 3H-thymidine injection. Isotope uptake of proliferative granulocytes was reduced by the chalone treatment. No such effect was found on the rat immunoblasts and macrophages. The viability of cultured cells was apparently not affected by the chalone treatment.  相似文献   

11.
Abstract. The proliferative response of lymphocytes to phytohaemagglutinin has been studied following incremental doses of 60Co gamma radiation delivered at the beginning of culture. A dose-dependent inhibition of 3H-thymidine uptake is apparent in 48 hr and 72 hr cultures throughout the 250–2000 rad range, and the effect appears more marked at the later labelling time. Parallel autoradiographic studies have revealed changes in the cell cycle kinetics of irradiated cultures which underlie the effects observed at the whole-culture level. Irradiation reduces the number of cells reaching the first period of DNA synthesis and causes dose-dependent delays at specific points in the cycle of proliferating cells.  相似文献   

12.
The purpose of these experiments was to determine whether materials physically present in, and modifying the activity of, the reticuloendothelial (RE) cells could influence selected metabolic functions in hepatic parenchyma, and modify the overall regenerative growth in partially resected livers. Induction of tyrosine transaminase by endotoxin or cortisone, and repression, of either endogenous or hormonally induced glyconeogenesis by the toxin, progressed as well in partially hepatectomized animals as in normal mice. The uptake, binding and association of 3H-cortisone with its receptors was largely uninfluenced by partial hepatectomy.
In doses that stimulate the RE function, administration of either bacterial endotoxin or cortisone resulted in a delayed burst of 3H-thymidine incorporation in regenerating livers. In, higher doses, cortisone lowered DNA synthesis associated with regeneration. Celite or bentonite also retarded the onset of DNA formation after partial hepatectomy. Moreover, the regenerative growth was almost completely eliminated in animals which had been rendered tolerant to bacterial endotoxin prior to surgery. Post-operative administration of bovine somatotropin, or phagocytosis of latex particles, however, did not influence the increased 3H-thymidine incorporation associated with the regenerative growth. These results are discussed as a model to explore possible intercellular co-operation regulating a variety of cellular responses.  相似文献   

13.
Abstract: Arachidonic acid (AA) markedly stimulated, in a dose-dependent manner, the spontaneous release of [3H]dopamine ([3H]DA) continuously synthesized from [3H]tyrosine in purified synaptosomes from the rat striatum. As estimated by simultaneous measurement of the rate of [3H]H2O formation (an index of [3H]tyrosine conversion into [3H]DOPA), the AA response was associated with a progressive and dose-dependent reduction of [3H]DA synthesis. In contrast to AA, arachidic acid, oleic acid, and the methyl ester of AA (all at 10−4 M ) did not modify [3H]DA release. The AA (3 × 10−5 M )-evoked release of [3H]DA was not affected by inhibiting AA metabolism, with either 5,8,11,14-eicosatetraynoic acid or metyrapone, suggesting that AA acts directly and not through one of its metabolites. AA also inhibited in a dose-dependent manner [3H]DA uptake into synaptosomes, with a complete blockade observed at 10−4 M . However, AA (10−4 M ) still stimulated [3H]DA spontaneous release in the presence of either nomifensine or other DA uptake inhibitors, indicating that AA both inhibits DA reuptake and facilitates its release process. Finally, the AA (10−4 M )-evoked release of [3H]DA was not affected by protein kinase A inhibitors (H-89 or Rp -8-Br-cAMPS) but was markedly reduced in the presence of protein kinase C inhibitors (Ro 31-7549 or chelerythrine).  相似文献   

14.
Following an injection of 3H-thymidine to mice there is no initial incorporation in small thymocytes, only in larger ones. In the course of time small thymocytes aquire the label. Whether the delayed uptake in small thymocytes is due to a direct cell to cell transfer of labelled nuclear material from inititally labelled larger cells to small thymocytes, or whether it is due to small thymocytes being formed from larger cells by mitotic division was investigated by the administration of Colcemid® immediately after one injection of 3H-thymidine. In the absence of cell division no labelled small thymocytes appeared with time. This finding does not support the idea of a cell to cell transfer of DNA; it rather lends support to the view that small thymocytes arise by mitotic division of larger cells in the thymus. During the treatment with Colcemid® the migration of cells took place from peripheral to central cortex just like under normal conditions.  相似文献   

15.
Abstract: The release of preloaded [14C]neuroactive amino acids (glutamic acid, proline, γ-aminobutyric acid) from rat brain synaptosomes can occur via a time-dependent, Ca2+ -independent process. This Ca2+-independent efflux is increased by compounds that activate Na+ channels (veratridine, scorpion venoms), by the ionophore gramicidin D, and by low concentrations of unsaturated fatty acids (oleic acid and arachidonic acid). Saturated fatty acids have no effect on the efflux process. Neither saturated nor unsaturated fatty acids have an effect on the release of [14C]leucine, an amino acid not known to possess neurotransmitter properties. The increase in the efflux of neuroactive amino acids by oleic and arachidonic acids can also be demonstrated using synaptosomal membrane vesicles. Under conditions in which unsaturated free fatty acids enhance amino acid efflux, no effect on 22Na+ permeability is observed. Since Na+ permeability is not altered by fatty acids, the synaptosomes are not depolarized in their presence and, thus, the Na+ gradient can be assumed to be undisturbed. We conclude that unsaturated fatty acids represent a potentially important class of endogenous modulators of neuroactive amino acid transport in nerve endings and further postulate that their action is the result of an uncoupling of amino acid transport from the synaptosomal Na+ gradient.  相似文献   

16.
Microbial sulfate reduction in acidic (pH 3) strip-mine lakes   总被引:3,自引:0,他引:3  
Abstract 35SO4 reduction was detected in slurries of sediments obtained from Reservoir 29 (pH 3.8) and Lake B (pH 6.2), two acid strip-mine lakes in Indiana. The rates varied seasonally and were higher in summer and fall than in the spring. The optimal pH for sulfate reduction in Reservoir 29 sediments was 5, but samples had increased activity at pH 7 within 24 h after adjusting the pH to this value. In Lake B, the optimal pH for sulfate reduction was the in situ pH (6.2). Sulfate reduction in both lakes was stimulated 2–3-fold by increasing p H2. High concentrations (5 mM) of organic acids inhibited sulfate reduction at pH 3.8, but stimulation was observed at concentrations of 0.1 mM. Acid-volatile sulfides accounted for about 70% of the products of 35SO4 reduction.  相似文献   

17.
Abstract: Effects of barbiturates, diphenylhydantoin, and ethanol on 45Ca2+ binding to acidic lipids have been examined in an organic solvent-aqueous partition system. Hexobarbital, pentobarbital, and phenobarbital, at concentrations of 0.3 and/or 0.6 mM, enhanced the binding of 45Ca2+ to phosphatidic acid, phosphatidylserine, and sulfatide but not to phosphatidylinositol or cardiolipin. Diphenylhydantoin, 0.3 mM, enhanced 45Ca2+ binding to phosphatidic acid and phosphatidylserine but not to sulfatide. Ethanol at 80 mM did not enhance 45Ca2+ binding to phosphatidic acid, but ethanol decreased the binding to cardiolipin and increased it to sulfatide.  相似文献   

18.
徐艳勤  陈立  王文凯 《昆虫学报》2018,61(12):1414-1420
【目的】工蚁死亡后易受病原菌的侵染,进而危害蚁巢的健康。为了避免病菌横向传播,活工蚁根据尸体体内特定的化学物质的变化来识别尸体并将其搬运到弃尸堆。本实验旨在研究6种脂肪酸(油酸、亚油酸、棕榈油酸、棕榈酸、硬脂酸和肉豆蔻酸)对红火蚁Solenopsis invicta工蚁搬尸行为的影响,明确不同脂肪酸在其搬尸行为中发挥的作用。【方法】本实验利用GC-MS分析了工蚁活体和尸体提取物的脂肪酸成分,并在室内用滤纸片法测定了红火蚁对6种脂肪酸(10 μg/μL)、不同浓度(0.75和3 μg/μL)的单组分油酸或亚油酸以及不同浓度(0.01, 0.1, 1和10 μg/μL)的这两种酸的混合液的反应。【结果】结果表明,红火蚁尸体仅含有亚油酸和油酸两种脂肪酸;另外4种脂肪酸(棕榈油酸、棕榈酸、硬脂酸和肉豆蔻酸)对红火蚁的搬尸行为无显著影响;单组分的油酸和亚油酸均能促进红火蚁的搬尸行为,浓度越高,搬尸行为越显著。10 μg/μL的油酸和亚油酸混合液对工蚁的搬尸行为也具有显著的促进效果,低浓度的混合液对其无明显的促进作用(P>0.05)。【结论】结果提示油酸和亚油酸可调控红火蚁的搬尸行为,其他脂肪酸对红火蚁搬尸行为不产生影响。  相似文献   

19.
The fatty acid composition of the total lipids from two Conidiobolus species was studied by gas—liquid chromatography. The major fatty acids of C. lamprauges were palmitic acid (C16:0), oleic acid (C18:1), linolenic acid (C18:3), and arachidonic acid (C20:4). For C. eurymitus , myristic acid (C14:0), C16:0, and linoleic acid (C18:2) were the most abundant acids. The fatty acid composition of C. eurymitus was quite different from that of the Conidiobolus species as mentioned in other reports. The lipid composition of the total lipids of C. lamprauges and C. eurymitus was also studied by thinchrography on quartz rods. Triglycerides and phospholipids were the major components in the two Conidiobolus species.  相似文献   

20.
Abstract— Brain slices were incubated with [3H]GABA in a medium containing aminooxyacetic acid to prevent metabolism of [3H]GABA by GABA-glutamate transaminase. The slices, which rapidly accumulated radioactivity, were then continuously perfused and the efflux of [3H]GABA from the tissue was measured. The spontaneous efflux of [3H]GABA consisted of an initial rapid phase followed by a much slower release of [3[H]GABA. After 40 min perfusion 90 per cent of the radioactivity remained in the tissue.
The slices were depolarized by electrical stimulation or by perfusion with a medium containing a high potassium concentration (40 mM). These procedures caused a striking increase in the efflux of [3H]GABA. The increased efflux produced by potassium, but not that produced by electrical stimulation, was dependent on calcium ions in the medium. The effect of electrical stimulation on [3H]GABA release was considerably reduced by a raised concentration (10 mM) of magnesium in the medium.
High potassium concentrations and electrical stimulation did not cause an increase in the efflux of [14C]urea, L-[3H]leucine or [14C]α-amino-isobutyric acid from brain slices. These results are consistent with the suggestion that GABA may be an inhibitory transmitter in the cerebral cortex.  相似文献   

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