首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
This study was carried out to determine the influence of short chain fatty acids (SCFA) on spleen and mesenteric lymph node lymphocyte proliferation, goblet cells and apoptosis in the mouse small intestine during invasion by Trichinella spiralis. BALB/c mice were infected with 250 larvae of T. spiralis. An SCFA water solution containing acetic, propionic and butyric acids (30:15:20 mM) was administered orally starting 5 days before infection and ending 20 days post infection (dpi). Fragments of the jejunum were collected by dissection 7 and 10 dpi, and were examined for apoptotic cells in the lamina propria of the intestinal mucosa, and for goblet cells. The proliferation index of the cultured spleen and mesenteric lymph node lymphocytes with MTT test was also determined. The orally administered SCFA solution decreased the proliferation of mesenteric lymph node lymphocytes in the mice infected with T. spiralis at both examination times, but did not influence the proliferative activity of the spleen cells. Seven dpi, both in the spleen and mesenteric lymph nodes, the highest proliferation index of concanavalin A (Con A)-stimulated lymphocytes was found in the group of uninfected animals receiving SCFA animals. This tendency could still be seen 10 dpi in the mesenteric lymph nodes but not in the spleen, where the proliferation index in this group had significantly decreased. In vitro studies revealed, that butyric and propionic acids added to the cell cultures suppressed the proliferation of Con A-stimulated mesenteric lymph nodes and spleen lymphocytes taken from uninfected and T. spiralis-infected mice. Acetic acid stimulated proliferation of splenocytes taken from uninfected mice but did not affect lymphocyte proliferation in mesenteric lymph nodes from uninfected or infected mice. Orally administered SCFA increased the number of goblet cells found in the epithelium of the jejunum 7 dpi, but this number had decreased 10 dpi. The number of apoptotic cells in the lamina propria of the intestinal mucosa of animals infected with the T. spiralis and receiving SCFA was also lower, particularly 10 dpi. The above results show that SCFA can participate in the immune response during the course of trichinellosis in mice.  相似文献   

2.
Germ-free (GF) and conventional (CV) C3H mice received a single injection of 1 μCi [3H]thymidine and 3 μCi [125I]iododeoxyuridine to provide simultaneous labeling of DNA with the two precursors. Thymus, spleen, mesenteric lymph nodes, bone marrow (femora), small intestine, colon and skin were examined for total organ activity and rate of DNA renewal 1–8 days after injection. Precursor incorporation, assayed on day 1, was lower in the thymus, mesenteric lymph nodes and femora (and, to a lesser extent, in the spleen and colon) of GF mice as compared to CV animals. The opposite was observed in the small intestine and skin, i.e. total organ activity was higher in GF animals. Differences in precursor incorporation were partly due to differences in organ weights between the two groups of mice. In comparison to CV animals, DNA renewal rates were diminished in the mesenteric lymph nodes, bone marrow, colon (following a 3-day plateau) and spleen of GF mice. Little, if any, difference was observed between the two groups with respect to the rate of DNA turnover in the thymus and skin. Radioactivity of the small intestine remained constant for 2 days. Thereafter intestinal activity in GF mice declined at an initial slow rate between days 2 and 5 followed by a rapid decrease between days 5 and 8. In CV mice the first phase of activity loss was short with the rapid decline in intestinal activity beginning on day 3. From the slopes of the regression lines, the percentage thymidine reutilization was estimated. Reutilization varied from 0 to 63% in the various organs examined, with the greatest difference between GF and CV mice occurring in the mesenteric lymph nodes.  相似文献   

3.
Between 2001 and 2004, 14 Austrian free-ranging red deer (Cervus elaphus hippelaphus) infected by Mycobacterium avium species were observed. Eight of the cases were from different geographical regions, and six originated from the same hunting area. The affected animals had signs of diarrhea, severe weight loss, and emaciation. On post-mortem examination, lymphadenitis associated with grossly enlarged mesenteric lymph nodes as well as multiple caseous or purulent nodular lesions in the thickened wall of the intestines were present in all animals. In 10 cases M. avium subsp. avium and in four cases M. a. hominissuis were isolated. In three red deer, a mixed infection with M. a. hominissuis and M. a. paratuberculosis was evident. Typing of M. a. avium and M. a. hominissuis isolates was performed by polymerase chain reaction (PCR) detection of insertion sequence IS901 and the virulence-associated macrophage-induced gene (mig), inverted repeat (IR) typing (IS1245/IS1311), and random amplified polymorph DNA (RAPD) analysis. While all M. a. avium and M. a. hominissuis contained the mig gene, IS901 was detected only in M. a. avium. The prevalence of IS901-positive isolates correlated well with the geographic location of affected animals. The IS901-containing isolates were shown to be genotypically closely related, as they exhibit similar patterns in IR-typing and in RAPD analysis. In contrast, IS901-negative isolates (M. a. hominissuis) displayed distinct profiles in both molecular systems.  相似文献   

4.
Methanogenic bacteria with a coccobacillus morphology similar to Methanobrevibacter ruminantium were isolated from the bovine rumen. One isolate, 10-16B, represented a previously undescribed rumen population that, unlike M. ruminantium, synthesized coenzyme M, grew rapidly (mu = 0.24 h-1) on H2-CO2 in a complex medium, had simple nutritional requirements, and metabolized formate at reported rumen concentrations. H2 was metabolized to partial pressures 10-fold lower than those reported for the rumen. After H2 starvation for 26 h, strain 10-16B rapidly resumed growth when H2 was made available. The minimum concentrations of acetate (6 mM) and ammonia (less than 7 mM) that were required for optimal growth were lower than the reported acetate and ammonia concentrations in the rumen. Isoleucine and leucine stimulated growth, but only at concentrations (greater than 50 microM) higher than those reported for the rumen. Another coccobacillary methanogenic organism that synthesized coenzyme M was isolated from a different animal as were organisms that required an exogenous supply of coenzyme M. In general, methanogenic bacteria that required an exogenous supply of coenzyme M had lower maximum growth rates and more complex nutritional requirements than organisms that synthesized the cofactor. The ability of all isolates to metabolize formate below the detection limit of 10 microM indicated that, in contrast to previous reports, methanogenic bacteria have the potential to directly metabolize formate in the rumen. This study demonstrated that there are physiologically diverse populations of coccobacillary methanogenic bacteria in the rumen that can interact competitively and cooperatively.  相似文献   

5.
The development of lymphoid cells reactive to tapeworm-associated antigens during the course of Hymenolepis diminuta rejection from mice was studied using an in vitro tapeworm extract (TWE)-induced cell proliferation culture system. Mice infected with three cysticercoids on day 0 developed three adult worms by day 7 but worms were rejected by day 21 post-infection. Concomitant with worm rejection was the development of TWE-sensitized lymphoid cells which responded by proliferation when stimulated in vitro with TWE. Sensitized cells were detected in gut-associated mesenteric lymph nodes but were not detected in spleen, axillary lymph nodes, or Peyer's patches of infected mice, or in lymphoid organs of non-infected mice. These studies suggest that rejection of H. diminuta from mice is associated with the activities of gut-associated, tapeworm antigen-sensitized immune cells localized in the mesenteric lymph nodes.  相似文献   

6.
Glutamine metabolism in lymphocytes of the rat.   总被引:24,自引:7,他引:17       下载免费PDF全文
The metabolism of glutamine in resting and concanavalin-A-stimulated lymphocytes was investigated. In incubated lymphocytes isolated from rat mesenteric lymph nodes, the rates of oxygen and glutamine utilization and that of aspartate production were approximately linear with respect to time for 60 min, and the concentrations of adenine nucleotides plus the ATP/ADP or ATP/AMP concentration ratios remained approximately constant for 90 min. The major end products of glutamine metabolism were glutamate, aspartate and ammonia: the carbon from glutamine may contribute about 30% to respiration. When both glucose and glutamine were presented to the cells, the rates of utilization of both substances increased. Evidence was obtained that the stimulation of glycolysis by glutamine could be due, in part, to an activation of 6-phosphofructokinase. Starvation of the donor animal increased the rate of glutamine utilization. The phosphoenolpyruvate carboxykinase inhibitor mercaptopicolinate decreased the rate of glutamine utilization by 28%; the rates of accumulation of glutamate and ammonia were decreased, whereas those of lactate, aspartate and malate were increased. The mitogen concanavalin A increased the rate of glutamine utilization (by about 51%). The rate of [3H]thymidine incorporation into DNA caused by concanavalin A in cultured lymphocytes was very low in the absence of glutamine; it was increased about 4-fold at 1 microM-glutamine and was maximal at 0.3 mM-glutamine; neither other amino acids nor ammonia could replace glutamine.  相似文献   

7.
Methanogenic bacteria with a coccobacillus morphology similar to Methanobrevibacter ruminantium were isolated from the bovine rumen. One isolate, 10-16B, represented a previously undescribed rumen population that, unlike M. ruminantium, synthesized coenzyme M, grew rapidly (mu = 0.24 h-1) on H2-CO2 in a complex medium, had simple nutritional requirements, and metabolized formate at reported rumen concentrations. H2 was metabolized to partial pressures 10-fold lower than those reported for the rumen. After H2 starvation for 26 h, strain 10-16B rapidly resumed growth when H2 was made available. The minimum concentrations of acetate (6 mM) and ammonia (less than 7 mM) that were required for optimal growth were lower than the reported acetate and ammonia concentrations in the rumen. Isoleucine and leucine stimulated growth, but only at concentrations (greater than 50 microM) higher than those reported for the rumen. Another coccobacillary methanogenic organism that synthesized coenzyme M was isolated from a different animal as were organisms that required an exogenous supply of coenzyme M. In general, methanogenic bacteria that required an exogenous supply of coenzyme M had lower maximum growth rates and more complex nutritional requirements than organisms that synthesized the cofactor. The ability of all isolates to metabolize formate below the detection limit of 10 microM indicated that, in contrast to previous reports, methanogenic bacteria have the potential to directly metabolize formate in the rumen. This study demonstrated that there are physiologically diverse populations of coccobacillary methanogenic bacteria in the rumen that can interact competitively and cooperatively.  相似文献   

8.
Elk (Cervus elaphus manitobensis) and white-tailed deer (Odocoileus virginianus) in the Riding Mountain National Park (RMNP) region of southwestern Manitoba have been identified as a likely wildlife reservoir of Mycobacterium bovis, the causative agent of bovine mycobacteriosis in livestock. The feasibility of using coyotes (Canis latrans) collected from trappers as a sentinel species was investigated. Retropharyngeal, mesenteric, and colonic lymph nodes and tonsils collected at necropsy from 82 coyotes were examined by bacterial culture, polymerase chain reaction (PCR), and acid-fast histopathology. Mycobacterium bovis was not identified in any animal by culture or PCR although Mycobacterium avium species were isolated. A single acid-fast organism was identified on histopathologic examination of one animal. Based on the methods used in this study, trapper-caught coyotes do not appear to be a sensitive sentinel species of M. bovis infection in cervids in and around RMNP.  相似文献   

9.
Role of sodium in the growth of a ruminal selenomonad   总被引:1,自引:0,他引:1  
The ruminal selenomonad strain H18 grew rapidly (mu = 0.50 h-1) in a defined medium containing glucose, ammonia, purified amino acids, and sodium (95 mM); little if any ammonia was utilized as a nitrogen source. When the sodium salts were replaced by potassium salts (0.13 mM sodium), there was a small reduction in growth rate (mu = 0.34 h-1), and under these conditions greater than 95% of the cell nitrogen was derived from ammonia. No growth was observed when the medium lacked sodium (less than 0.35 mM) and amino acids were the only nitrogen source. At least six amino acid transport systems (aspartate, glutamine, lysine, phenylalanine, serine, and valine) were sodium dependent, and these systems could be driven by an electrical potential (delta psi) or a chemical gradient of sodium. H18 utilized lactate as an energy source for growth, but only when sodium and aspartate were added to the medium. Malate or fumarate was able to replace aspartate, and when these acids were added, sodium was no longer required. Glucose-grown cells accumulated large amounts of polysaccharide (64% of dry weight), and when the exogenous glucose was depleted, this material was converted to acetate and propionate as long as sodium was present. When the cells were incubated in buffers lacking sodium, succinate accumulated and exogenous succinate could not be decarboxylated. Because sodium had little effect on the transmembrane pH gradient at pH 6.7 to 4.5, it did not appear that sodium was required for intracellular pH regulation.  相似文献   

10.
Mycobacterium avium strain 104 was chosen as the M. avium isolate to sequence, as it is virulent to humans, stable and readily transfectable. As this strain has not been widely studied we sought to investigate the pattern of 104 infection in mice. Bacterial growth and the immune response generated were compared with infection with the low virulence M. avium strain 100, and the high virulence common laboratory strain, 101. Mycobacterium avium strains 104 and 101 grew progressively within mice, while strain 100 was gradually cleared. Strains 104 and 101 induced strong T cell activation and spleen cell cultures produced similar levels of IFN-gamma. In mice infected with strain 100 no significant T cell activation or IFN-gamma production was measured. Further, mice infected with strain 104 or 101 also displayed comparable inflammatory responses and similar granuloma formation, while only minimal inflammation was seen in mice infected with strain 100. Strains 101 and 104 also grew in a similar fashion in bone-marrow-derived macrophages and induced significant levels of TNF and nitric oxide. Thus infection with M. avium strain 104 induced an immunological response comparable to M. avium strain 101 and, with the availability of its sequence, should be a useful tool for designing new vaccines or drugs therapies to treat the increasing incidence of M. avium infection in humans.  相似文献   

11.
The maximal activity of key enzymes of glycolysis, pentose phosphate pathway, TCA cycle and glutaminolysis were measured in the immune tissues of rats fed w-3 PUFA during 6 weeks. Total lipid peroxidation and glutathione peroxidase activity were also measured. The hexokinase activity was enhanced 4-fold in the spleen and thymus, doubled in the liver and was diminished in mesenteric lymph nodes (35%). Citrate synthase activity was decreased in the spleen and lymph nodes and increased in the thymus. G-6-PDH activity was increased 2-fold in the spleen and mesenteric lymph nodes and by 20% in the thymus whereas it was reduced (66%) in the liver. Glutathione peroxidase activity and total lipid peroxides increased in all tissues of rats fed w-3 PUFA. The results presented here suggest that w-3 PUFA, by causing important metabolic changes in the immune tissues and lipid peroxidation may lead to changes of immune function.  相似文献   

12.
Isolation and structure elucidation was carried out of flavonoid constituents found in fractionated extracts of the seeds and green leaves of Daucus carota L. var. boissieri (Apiaceae). The flavonoids are mainly apigenin, luteolin, their glycosidic precursors and 2,4,5-trimethoxybenzaldehyde. Fatty acids, hydrocarbons and sterols were identified by GLC. The effect of various carrot extracts on the immune responses of Schistosoma mansoni infected mice was studied. The rate of reduction in worm infestation in mice injected with some fractions indicated a strong protection. Some extracts induced humoral immune response through raising the IgG level at 2, 4 and 6 weeks post-infection as compared with infected control. The phenotypic analysis of the cellular immune response in spleen and mesenteric lymph nodes was accomplished by direct immunofluorescence. The data showed that some extracts stimulated the blastogenesis of CD4(+)-T splenocytes and mesenteric lymph node cells.  相似文献   

13.
Pseudomonas aeruginosa infection depresses contact sensitivity to oxazolone in mice. To test whether an altered lymphocyte circulation plays a role in this depression51Cr-labeled lymphocytes fromP. aeruginosa-infected and oxazolone-sensitized donors were injected intravenously into infected and sensitized recipients, and the radioactivity uptake of several organs was determine. The controls consisted of normal mice receiving labeled lymphocytes from normal donors. While the radioactivity recovered from the liver, spleen, and mesenteric lymph nodes was similar in the test and the control group, significantly more radioactivity was recovered from the draining lymph nodes of infected and sensitized recipients. The concentration of labeled lymphocytes from sensitized donors in the draining lymph nodes of sensitized recipients was 18% greater than that of the controls but 31% lower than that of infected and sensitized animals receiving cells from infected and sensitized donors.P. aeruginosa infection enhances lymphocyte entrapment within the draining lymph nodes of oxazolone-sensitized mice.  相似文献   

14.
Role of sodium in the growth of a ruminal selenomonad.   总被引:1,自引:1,他引:0       下载免费PDF全文
The ruminal selenomonad strain H18 grew rapidly (mu = 0.50 h-1) in a defined medium containing glucose, ammonia, purified amino acids, and sodium (95 mM); little if any ammonia was utilized as a nitrogen source. When the sodium salts were replaced by potassium salts (0.13 mM sodium), there was a small reduction in growth rate (mu = 0.34 h-1), and under these conditions greater than 95% of the cell nitrogen was derived from ammonia. No growth was observed when the medium lacked sodium (less than 0.35 mM) and amino acids were the only nitrogen source. At least six amino acid transport systems (aspartate, glutamine, lysine, phenylalanine, serine, and valine) were sodium dependent, and these systems could be driven by an electrical potential (delta psi) or a chemical gradient of sodium. H18 utilized lactate as an energy source for growth, but only when sodium and aspartate were added to the medium. Malate or fumarate was able to replace aspartate, and when these acids were added, sodium was no longer required. Glucose-grown cells accumulated large amounts of polysaccharide (64% of dry weight), and when the exogenous glucose was depleted, this material was converted to acetate and propionate as long as sodium was present. When the cells were incubated in buffers lacking sodium, succinate accumulated and exogenous succinate could not be decarboxylated. Because sodium had little effect on the transmembrane pH gradient at pH 6.7 to 4.5, it did not appear that sodium was required for intracellular pH regulation.  相似文献   

15.
An agonist such as carbamylcholine or phenyltrimethylammonium induced a second, slower complete inactivation of acetylcholine receptor prepared from Electrophorus electricus. The rate of this inactivation of the receptor followed first-order kinetics. The rate constant of the inactivation increased with the agonist concentration until it reached a plateau, the value of which was 0.19 h-1 at 4.5 degrees C. The reaction was also temperature dependent, and the activation energy of the inactivation caused by 1 mM carbamylcholine was estimated to be 7.6 kcal/mol. The inactive receptor was reconverted to the active form with a rate constant of about 0.015 h-1 at 4.5 degrees C when the carbamylcholine concentration (0.1 mM) was reduced by 15-fold dilution in eel Ringer's solution. These results can be interpreted by adding, to the minimal reaction scheme proposed by the Hess group, a second, slower, reversible inactivation process either through the intact form or through the first desensitized form of the receptor binding two agonist molecules.  相似文献   

16.
Several attempts were made to colonize the alimentary tract and infect germfree BALB/c mice and germfree Sprague-Dawley rats with two human isolates of Helicobacter pylori. The alimentary tracts of mice, sacrificed at intervals between 1 day and 20 weeks after oral challenge, were culture negative for H. pylori. The alimentary tract, kidney, liver, and mesenteric lymph nodes were culture negative for H. pylori 5 h after intravenous challenge. Growth of H. pylori was inhibited by homogenates of murine stomach, small intestine, liver, and mesenteric lymph nodes. Germfree rats and mice do not appear to be readily colonized or infected by human strains of H. pylori.  相似文献   

17.
A survey was carried out to verify if an immunohistochemical method associated with agar gel immunodiffusion (AGID) will establish a firm diagnosis of caprine paratuberculosis. One hundred and thirty-six goats were tested by AGID for antibodies against Mycobacterium avium subsp. paratuberculosis at two different times: the first time 22 (19.1%) were positive and the second time 25 (18%). One seronegative goat with severe diarrhea and 5 seropositive goats, two of which showing similar clinical signs, were sacrificed and necropsied. Samples were taken from small intestine, liver, spleen, mesenteric lymph nodes for bacteriological, histological and immunohistochemical examinations. M.a. paratuberculosis was isolated from intestine samples of 4 seropositive goats and from mesenteric lymph nodes of one seropositive goat; the microorganism was not isolated from samples of one seropositive and the seronegative animals. Ziehl Neelsen staining showed acid-fast bacilli in macrophages of the 5 seropositive animals and the immunohistochemical method for M. a. paratuberculosis detected bacterial antigen in the same samples.  相似文献   

18.
The maintenance energy coefficient of Desulfovibrio vulgaris was studied by using a chemostat, with Methanosarcina barkeri or sulfate as the electron acceptor; lithium lactate or sodium pyruvate served as the electron donor. The experiments showed that the growth energetics of D. vulgaris or M. barkeri were greatly affected by maintenance energy coefficients. When D. vulgaris grew on lactate or pyruvate medium with sulfate, these coefficients reached 4.40 and 2.80 mM g-1 h-1, respectively; on lactate medium in the presence of M. barkeri the same coefficient reached a value of 2.90 mM g-1 h-1. Results also showed that the increase of the value of the maintenance energy coefficient corresponded to a decrease of the biomass produced. D. vulgaris maximal growth yield values calculated by use of the Pirt equation were slightly higher with M. barkeri (maximal growth yield, 10 g/mol) than with sulfate (maximal growth yield, 7.5 g/mol). This finding could be interpreted by reference to the ATP-generating reactions involved in D. vulgaris growth in the presence of sulfate or M. barkeri.  相似文献   

19.
We defined the role of the syrphid fly Eristalis tenax in the survival and transmission of mycobacteria in pigs. The conditionally pathogenic mycobacterial (CPM) species Mycobacterium chelonae was isolated from 10 % of liquid dung samples, and both M. chelonae and another CPM species M. fortuitum were isolated from 7 (78 %) of the examined E. tenax larvae collected from the same location. Mycobacteriosis of the lymph nodes of pigs from 3 infected farms was caused by M. avium subsp. avium, M. avium subsp. hominissuis, and M. fortuitum. M. avium subsp. avium and M. avium subsp. hominissuis of identical genotype and serotypes and M. fortuitum were isolated from 7 (1.9 %) larvae, 2 (7.4 %) puparia, and one (1.6 %) imago. The count of colony forming units isolated from larval skin covering (pouch) was higher (p < or = 0.01) than that isolated from the internal organs of larvae. These results showed the potential for E. tenax larvae to spread mycobacteria throughout pig herds and the surrounding environment.  相似文献   

20.
Susceptible BALB/c mice were infected iv with a strain of Mycobacterium avium and infused with different biological response modifiers (BRM) in a gel delivery system so as to modify the progression of the infection in a beneficial fashion. Infusion of IL-2 or IL-4 in hydrophobic gels led to no significant enhancement of resistance. Infusion of muramyl dipeptide in hypromellose led to a significant enhancement of resistance against the M. avium, as seen by a significant reduction of colony-forming units (CFU) in the spleens of infected mice. Similarly, infusion of interleukin-1 beta in hypromellose in infected mice led to a significant reduction in CFU counts in the organs of mice. The mechanism(s) responsible for this enhanced resistance was studied further. It was found that infected mice developed profound immunosuppression, as judged by mitogenic and antigenic stimulation. Mice infused with MDP/hypromellose developed a similar immuno-suppression, suggesting that this adjuvant immunotherapy did not act by stimulating a T-cell response or by abrogating a putative suppressive phenomenon. Macrophages from mice infused with MDP alone were no more bacteriostatic for a virulent M. avium than control cells. However, macrophages from infected mice infused with MDP/hypromellose were more bacteriostatic for M. avium than cells from mice infected with M. avium and infused with the hydrophobic gel only. Overall, these results suggest that adjuvant immunotherapy is beneficial in M. avium infections.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号