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1.
Nine inbred murine strains were either highly resistant or highly susceptible to intravenous challenge with 4 X 10(4) to 1 X 10(5) cells of Candida albicans. The resistant strains had the capacity to develop delayed footpad reactions on appropriate sensitization and challenge; the susceptible strains did not have this innate capacity. Administration of thymosin fraction 5 beginning on the day of infection greatly increased the resistance of the susceptible strains to infection, but decreased the resistance of the resistant strains. In contrast, thymosin fraction 5 enhanced the delayed footpad responses of resistant-sensitized mice to specific antigen, but did not have a detectable effect on the delayed footpad reactions of the susceptible strains. Reinfection of the two types of strains had different effects, in that, depending on the strain, resistance could be increased, decreased, or not influenced at all.  相似文献   

2.
Studies on an anophthalmic strain of mice. VI. Lens and cup interaction   总被引:1,自引:0,他引:1  
In the embryology of the eye region in the anophthalmic strain of mice (ZRDCTCh), development proceeds normally until Day 10 (26 somites). At this time a lens is induced, but it is smaller in size and may be improperly centered in the optic cup. Where the lens is centered in relation to the optic cup determines whether microphthalmia or anophthalmia will occur. Also, we observed that optic cup formation is different in normal control strains.  相似文献   

3.
Using six mouse strain combinations, we attempted to prolong cardiac allograft survival by pretreatment of recipients with a single iv injection of donor-specific whole blood or spleen cells plus a single ip injection of cyclophosphamide (Cy). Significant prolongation of cardiac allograft survival occurred in a small proportion of pretreated mice of some strain combinations, with some grafts surviving for periods longer than 6–9 months. Cy injected alone did not influence the normal cardiac allograft rejection time of between 1 and 2 weeks. Depending upon the strain combination, accelerated rejection of all or some of the grafts occurred in mice pretreated with blood or spleen cells or myocardial cells alone.  相似文献   

4.
The response of rat liver plasma membrane adenylate cyclase was studied from one to 14 days after a single dose of carbon tetrachloride (CCl4). The response to glucagon was diminished to a greater extent than that of fluoride and was due to a deficiency in hormone binding. In contrast, insulin binding increased 300% over control; the change was due to increased number of binding sites. The “affinities” of receptors for either hormone were not altered. The tissue levels of adenosine 3′:5′ -monophosphate increased following CCl4 poisoning reaching a peak precisely when the adenylate cyclase response to glucagon was at its lowest level. These studies present evidence that receptors for pancreatic hormones change differently when liver is damaged and during its regeneration following CCl4 intoxication. The change in pattern is remarkably similar to changes reported previously in fetal liver development or following partial hepatectomy of adult rat.  相似文献   

5.
We have examined in two inbred rat strains basal and stress-induced increases in plasma levels of epinephrine (EPI) and norepinephrine (NE) and compared these with activities of the adrenal enzymes involved in the synthesis of catecholamines. There were no differences in basal levels of NE and EPI in plasma of adult male rats of the Wistar-Kyoto (WKY) and Brown-Norway (B-N) strains. However, following 5 min. of intermittent footshock, plasma levels of both catecholamines were twice as high in WKY rats as in B-N rats. In the adrenals of unstressed rats, activities of tyrosine hydroxylase and dopamine-beta-hydroxylase were significantly higher in B-N rats. In addition, the adrenal weights and the contents of NE but not EPI were greater in B-N rats. Thus, in these two rat strains, the capacity of the adrenal gland to synthesize and store catecholamines appeared to be inversely related to plasma levels of NE and EPI after stress. The differences between the strains appeared to be due to differences in the rates of removal of catecholamines from the peripheral circulation as well as to differences in the rate of release of catecholamines from the sympatho-adrenal medullary system. Thus biosynthetic enzyme activities need not be related directly to the capacity to release and elevate plasma levels of catecholamines following stressful stimulation.  相似文献   

6.
Guinea pig peritoneal macrophages were activated in vitro by culturing with MAF (macrophage activating factor)-containing fractions from stimulated lymphocytes. These macrophage preparations demonstrate a 60% increase in the production of prostaglandins of the E series (PGE) when compared with macrophages cultured with fractions from unstimulated lymphocytes. PGE accumulation in macrophage cultures is maximal after 24 hr with MAF; tumor cytotoxicity is also maximal at this time. The final PGE concentration in cultures of activated macrophages averaged 3 × 10?8M.  相似文献   

7.
Divalent cations (Zn, Mn, Ba, Sr) inhibit the development of dormant gemmules of the freshwater sponge Spongilla lacustris. This inhibition is overcome by calcium which can be interpreted to mean that this divalent ion is essential for germination (cell division) in this system. Inhibitory divalent cations have different effective concentrations which indicate differing binding affinities for sites which may normally bind calcium. Ethylene glycol bis(β-aminoethyl ether)N,N-tetraacetic acid does not effect gemmule development at 15°C but stimulates it at 4°C, indicating that a dislocation of endogenous calcium stimulates release from dormancy. Magnesium will only partially substitute for calcium in overcoming divalent cation inhibition implying a different specificity for this ion in gemule development. Calcium is also indicated as being essential for hatching (cell motility) in this system.  相似文献   

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10.
Experiments were conducted in order to determine the energy source and nature of the cation dependency of [3H]methionine transport in preimplantation mouse embryos. The energy source of methionine transport was studied at the late four-cell and early blastocyst stages. The embryos, raised in vitro, were incubated for 1 hr in inhibitor(s) of energy metabolism and then transferred for 1 hr to medium that contained inhibitor(s) and 3H-methionine. These inhibitor studies suggest that respiration and glycolysis are needed to maintain uptake of methionine in early blastocysts. Late four-cell embryos seem to utilize respiration alone for transport.The cation dependency of methionine transport was studied at the late morula and early blastocyst stages. The kinetics of methionine uptake by early blastocysts in Na+-depleted media indicate a competitive type of inhibition. The uptake of methionine by early blastocysts is relatively resistant to ouabain and unaffected by K+-free medium. In contrast, methionine uptake by late morula-stage embryos is markedly inhibited by ouabain and K+-free medium in 1 hr. These results suggest that 1) Na+ serves to increase the affinity of methionine for the carrier in early blastocysts, 2) the cation gradients do not supply a major fraction of the energy required for methionine transport, and/or the gradients are difficult to perturb once the blastocyst has formed, and 3) putative Na+ pumps may be localized on the blastocoelic surface of the blastocysts.  相似文献   

11.
A stabilizing factor, previously reported to protect phosphofructokinase (EC2.7.1.11) from thermal or lysosomal inactivation, has been shown to stabilize ATP-citrate lyase (EC 4.1.3.8) from thermal inactivation (B. Osterlund and W. A. Bridger, 1977, Biochem. Biophys. Res. Commun., 76, 1–8). We now report that this factor protects ATP-citrate lyase from inactivation by proteases extracted from lysosomes. While it has been suggested that the stabilizing factor may play a role in the turnover of other lipogenic enzymes, we have found that the factor has no stabilizing or other effects on NADP+-malic enzyme (EC 1.1.1.40). In order to assess the properties and mode of action of the stabilizing factor with regard to interaction with its target enzyme(s), the factor has been extensively purified from rat liver and characterized as to its composition. Although glutathione appears to copurify with the factor, and glutathione exerts some stabilizing effects on ATP-citrate lyase, the factor is clearly distinguishable from glutathione on the basis of its mode of action and its concentration dependence. Several other biological compounds have been tested in attempts to identify the chemical nature of the stabilizing factor. Thus, biotin, pyridoxal phosphate, glucose tolerance factor, substrates for ATP-citrate lyase, and oxidized glutathione have been eliminated as possible identities for the stabilizing factor. In contrast to results reported by other workers (who investigated stabilization of phosphofructokinase) we find this factor to be insensitive to treatment by proteases or sulfhydryl reagents when tested by its ability to protect ATP-citrate lyase from inactivation.  相似文献   

12.
Partial purification and characterization of DNA-dependent RNA-polymerases from nauplius larvae of the brine shrimp, Artemia salina, are described. Fractionation of solubilized RNA-polymerases on columns of DEAE-cellulose yielded partially purified preparations of RNA polymerases I and II. The properties of these enzymes were found to be similar to properties of corresponding enzymes from other animal sources. A significant change in the relative amounts of polymerases I and II occurs between 36 and 72 hr of development. Polymerase activity obtained from 36-hr nauplii consisted of approximately equal amounts of polymerases I and II, whereas polymerase II accounted for more than 80% of the activity recovered from 72-hr nauplii. Total polymerase activity was lower at 72 than at 36 hr. The significance of these changes in relation to the decrease in RNA synthesis in vivo that occurs after 36 hr is discussed.  相似文献   

13.
Eight neutral oligosaccharide fractions were obtained from the pooled urine of two patients with mannosidosis by Bio-Gel P2 and Bio-Gel P4 column chromatography. The structures of seventeen oligosaccharides were determined by monosaccharide composition analysis, methylation studies, acetolysis, Smith degradation, and 13C NMR analysis. Three of the proposed structures, Manα1-3Manβ1-4GlcNAc, Manα1-2Manα1-3Manβ1-4GlcNAc, and Manα1-2Manα1-2Manα1-3Manβ1-4GlcNAc are identical to those first published by Norden et al. (N. E. Norden, A. Lundblad, S. Svennson, P. A. Ockerman, and S. Autio, 1973. J. Biol. Chem.248, 6210–6215; N. E. Norden, A. Lundblad, S. Svennson, and S. Autio, 1974. Biochemistry13, 871–874). Thirteen of them, Manα1-3Manα1-6(Manα1-3)-Manβ1-4GlcNAc, Manα1-3Manα1-6(Manα1-2Manα1-3)Manβ1-4GlcNAc, and 11 isomers of (Manα1-2)0–4[Manα1-6(Manα1-3)Manα1-6(Manα1-3)Manβ1-4GlcNAc], are the same as those first published by Yamashita et al. (K. Yamashita, Y. Tachibana, K. Mihara, S. Okada, H. Yabuuchi, and A. Kobata, 1980, J. Biol. Chem.255, 5126–5133); a tetrasac-charide, Manα1-6(Manα1-3)Manβ1-4GlcNAc, is newly reported and several other structural possibilities are proposed.  相似文献   

14.
The abilities of human monocytes differentially expressing HLA-DR and of lipopolysaccharide (LPS) to influence T-cell colony responses were investigated. Optimal T-cell colony responses stimulated by soluble Staph protein A were crucially dependent on monocytes. Also, monocyte facilitation of colony responses was markedly inhibited by 10 μg/ml LPS and the addition of indomethacin reversed this inhibition. In contrast the inhibition of T-cell colony responses with 100 μg/ml LPS was not reversed with indomethacin and preincubation experiments with high concentrations of LPS showed the inhibition could be mediated through T cells by mechanisms other than prostaglandins. The treatment of monocytes with a monoclonal anti-HLA-DR reagent + C reduced the frequencies of monocytes expressing high levels of HLA-DR ~ fivefold and the resulting monocytes which expressed low levels of HLA-DR also poorly functioned in the promotion of colony responses compared to controls. LPS in the presence of indomethacin improved the ability of monocytes expressing low levels of HLA-DR to promote colony responses. However, these monocytes consistently failed to augment colony responses to those levels observed with untreated monocytes and their failure was not secondary to deficient interleukin 1 release. These results indicate that although LPS can somewhat potentiate the accessory cell function of certain human monocytes, it cannot abrogate an additional requirement for those monocytes expressing high levels of HLA-DR.  相似文献   

15.
Intact and castrated male rats were injected with a single dose of estrogen (75 μg), followed by progesterone (1 mg) or by oil. Intact males showed higher lordosis quotients as compared to castrated males. Progesterone facilitated lordosis behavior in castrated as well as in intact males. An estrogen-progesterone treated group of sexually inactive male rats and of sexually exhausted males showed lower levels of lordosis as compared to the intact sexually active males.  相似文献   

16.
Cytochalasin B inhibits the penetration of sperm nuclei into Urechis eggs without inhibiting sperm-induced egg activation. The acrosome reaction appears normal, and plasma membranes of the acrosomal tubule and egg become closely apposed. It is uncertain whether or not the drug blocks fusion of these membranes; however, sperm penetration cone formation is inhibited.  相似文献   

17.
This report examines the histochemical staining patterns, ultrastructure, and cell-surface phenotypes of six antigen-specific T-cell clones. Histochemical analyses indicated that all cell lines expressed alpha-napthyl butyrate esterase characteristic of the monocytic isoenzyme, intense napthol AS-D chloroacetate reactivity characteristic of granulocytes, and were negative for leucoperoxidase, alkaline phosphatase, and Sudan black. Only one clone stained weakly for acid phosphatase. The esterase staining patterns became evident in newly established cell lines after growth for only 1 week in interleukin 2-conditioned medium. Ultrastructurally, the outstanding feature was numerous membrane-bound granules containing a complex-appearing globular material. The cell-surface phenotypes of the lines as determined by protein A-sheep red blood cell rosetting and indirect immunofluorescence was Ly-5+, T200+, Qa-5-, MAC-1-, and Lyt-1+,2,3- for the helper line and Lyt-1-2,3+ for the five cytotoxic lines. By quantitative absorption analyses, low levels of Lyt-1 antigens were detected on all examined cytotoxic lines. The results strengthen the view that long-term T-cell lines can retain normal T-cell characteristics while also expressing markers that are either absent or in undetectable levels on uncultured T lymphocytes. The presence of the esterases may be associated with an expanded functional role in the T-cell lines.  相似文献   

18.
Bilateral lesions of the ventromedial nucleus of the hypothalamus interfered with the estrogenic induction of sexual receptivity in the female rat, but seemingly did not affect the ability of female rats to show lordosis following combined stimulation with estrogen and progesterone. In addition, ventromedial hypothalamic lesions did not affect the ability of females to show male-like sexual activity in response to exogenous androgenic stimulation.  相似文献   

19.
The purpose of the present paper is to study the exchange rate of the hydrogen at the C-2 position of the thiazolium ring in thiamin and its polyphosphoric esters, by NMR spectroscopy. This rate is determined by following the corresponding signal intensity of the NMR spectrum in 2H2O.It has been found that the rate of exchange increases with pH, and that this increase is greater as the polyphosphoric chain becomes longer.Data show us that the half-life time of this exchange for thiamin at a pH value of about 9 is the same as that for diphosphothiamin at a lower pH range.  相似文献   

20.
S1 nuclease (EC 3.1.30.1) of Aspergillus oryzae has been purified 1600-fold by a procedure designed to remove traces of contaminating phosphatases. The nearly homogeneous enzyme was found to be a glycoprotein with a carbohydrate content of 18%. At pH 4.5 the enzyme preparation hydrolyzed single-stranded DNA, RNA, 3′-AMP, and 2′-AMP at relative rates of 100, 52, 13, and 0.05, respectively. The 3′-nucleotidase activity of this single-strand specific nuclease is inhibited by single-stranded DNA but not by double-stranded DNA. Three forms of the enzyme, with isoelectric points of 3.35, 3.53, and 3.67, were observed on electrofocusing, and each form exhibited the same relative activity on single-stranded DNA and 3′-AMP. Enzymatic hydrolysis of nucleotides occurred over a broad range of pH, with maximal activity at pH 6–7. Ribonucleotides were hydrolyzed approximately 100-fold more rapidly than deoxyribonucleotides. A high degree of base specificity was not observed. The 3′-nucleotidase activity was stimulated by Zn2+, but not by other divalent cations tested.  相似文献   

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