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 15 毫秒
1.
Cortisone (CA) or cyclophosphamide (Cy) treatment of mice was used to investigate the relative contributions of pulmonary alveolar macrophages (PAM) and inflammatory neutrophils (PMN) in the initial defense against intratracheal challenge (IT) with Candida albicans. Mice treated with either CA or Cy were susceptible to IT challenge with 10–100 x less C. albicans than were untreated mice. Untreated mice rapidly eliminated C. albicans from their lungs with the majority of the organisms being cleared within three hours of challenge. Mice treated with CA initially cleared some of the C. albicans but were unable to clear all the C. albicans as did the untreated mice. Mice treated with Cy were unable to clear C. albicans from their lungs. Candida albicans did not disseminate from the lungs of untreated mice, while in both of the treated groups, C. albicans disseminated to the liver, spleen, brain and kidneys, rapidly killing the treated hosts. Analysis of the changes in cells in lung lavage fluids collected at various times after C. albicans challenge, revealed that large numbers of PMN accumulated in the lungs of both untreated and CA-treated mice, whereas PMN were virtually undetectable in lavage fluids from Cy-treated mice. Resident PAM from untreated mice were able to kill approximately 70 % of 105 C. albicans in a 3 hr in vitro killing assay. By contrast, at similar effector: target ratios, resident PAM from Cy-treated mice killed only about 20% of the inoculum and resident PAM from CA-treated mice were unable to kill C. albicans. PMNs from both untreated and CA-treated mice killed approximately 70% of 105 C. albicans in vitro. The data indicates that both PAM and PMN were critical to the initial clearance of C. albicans from pulmonary tissue. The accumulation of PMN in the lungs appeared to be required for the complete clearance of C. albicans from the lungs yet was not sufficient to inhibit dissemination of C. albicans from the lungs in CA-treated mice. The presence of PAM with in vitro candidacidal abilities appeared to be required for both the clearance of C. albicans and inhibition of dissemination of C. albicans from the lungs. Compromise of either PAM or PMN function can lead to increased pulmonary susceptibility to C. albicans.  相似文献   

2.
The initial interaction of Candida albicans with pulmonary tissue of B6D2/F1 mice was investigated. The LD50 for mice challenged intravenously (IV) was approximately 3 × 105 yeasts, whereas the LD50 by the intratracheal (IT) route was in excess of 108 yeasts. Mice challenged IV died of progressive yeast growth in the kidneys. In contrast, mice challenged IT rapidly eliminated the entire inoculum by the first day after challenge. Resident pulmonary alveolar macrophages (PAM) killed upwards of 70% of C. albicans in an in vitro killing assay. At effector: target ratios favoring the effector cell population resident PAM were able to restrict the formation of yeast germ tubes to only 30% of the yeasts, whereas at equivalent ratios virtually all of the intracellular yeasts produced germ tubes. Evaluation of the ability of PAM, harvested from genetically different strains of inbred mice, to kill C. albicans in vitro showed that killing ability was a property of resident PAM from mice with the black 6 background. It was discovered that during the initial stages of infection in vivo, the expression of the F4/80 surface molecule was down regulated, and the expression of the Mac 1 surface molecule upregulated. There were no quantitative changes in expression of either Mac 2, Mac 3, Ly 5 or the 5C6 surface epitopes. Taken together, the data show that pulmonary tissue is quantitatively very resistant to C. albicans infection, because of the ability of resident PAM to rapidly phagocytize and kill yeasts. Killing of C. albicans by resident PAM may be a property of a subset of this mononuclear phagocyte population and was accompanied by alterations in the expression of surface molecules.Presented as part of the Everett S. Beneke Symposium in Mycology, May 27, 1988.  相似文献   

3.

Antilipopolysaccharide factors (ALFs) are important effectors of innate immunity in crustaceans with broad spectrum antimicrobial activity. Present study deals with the molecular and functional characterization of a 98-amino acid ALF isoform from, crucifix crab, Charybdis feriatus termed as Cf-ALF2. The ALF isoform Cf-ALF2 exhibits characteristic features of an AMP including a cationic net charge of + 9 and a total hydrophobic ratio of 34%. Recombinant peptide rCf-ALF2 showed remarkable antimicrobial activity against Gram-negative and Gram-positive bacteria especially against Staphylococcus aureus (minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 5 µM) and Escherichia coli (MIC 10 µM and MBC 20 µM). Using scanning electron microscopy, bacterial membrane blebbing, disruption, and cell content leakage were observed in peptide treated E. coli. The recombinant peptide was found to be non-hemolytic and non-cytotoxic in NCI-H460 cell line at the highest tested concentration (20 µM). Thus, this study identified a novel isoform of ALF from C. feriatus and revealed the potent antimicrobial property of the recombinant peptide Cf-ALF2 and the future prospects of using the peptide for therapeutic applications in the future.

  相似文献   

4.
High pressure homogenization (HPH) offers new opportunities for food pasteurization/sterilization. Escherichia coli and Staphylococcus aureus suspended in phosphate buffered saline (PBS) buffer, milk and apple juice at initial concentration of ~106 log10 CFU per ml were subjected to HPH treatments up to 200 MPa with inlet temperatures at 4–40°C. After HPH at 200 MPa with the inlet temperature at 40°C, the count of E. coli suspended in PBS, milk and apple juice reduced by 3·42, 3·67 and 3·19 log10 CFU per ml respectively while the count of S. aureus decreased by 2·21, 1·02 and 2·33 log10 CFU per ml respectively suggesting that S. aureus was more resistant. The inactivation data were well fitted by the polynomial equation. Milk could provide a protective effect for S. aureus against HPH. After HPH at 200 MPa with the inlet temperature at 20°C, the cell structure of E. coli was destroyed, while no obvious damages were found for S. aureus.  相似文献   

5.
Cirrhotic ascites are highly susceptible to spontaneous bacterial infection, whereas carcinogenic ascites are seldom infected. This difference may be explained by differences in their chemotactic, bactericidal and/or opsomic activities. We measured the chemotactic and opsonic activity of ascitic fluids from 35 alcoholic cirrhotic ascites and of 12 peritoneal carcinogenic ascites. Chemotactic activity was measured by the under-agarose technique and opsonic activity by a luminol-enhanced method. Ascitic fluids from alcoholic cirrhosis had low chemotactic (62 ± 24.5% that of N-formylated peptide) and opsonic (67 ± 50% of normal serum) activities on normal human neutrophils. In contrast, ascitic fluids from peritoneal carcinoma were found to possess high opsonic activity (114 ± 49% of normal serum) and chemotactic activity similar to that of N-formylated peptide. During a 3-month follow-up, 11 spontaneous bacterial infections were observed among the first group against none in the carcinogenic group.  相似文献   

6.
Two pathogenic microorganisms Escherichia coli O157:H7 and Staphylococcus aureus, suspended in peptone solution (0.1% w/v) were treated with 12, 14, 16 and 20 kV/cm electric field strengths with different pulse numbers up to 60 pulses. Pulsed electric field (PEF) treatment at 20 kV/cm with 60 pulses provided nearly 2 log reduction in viable cell counts of E. coli O157:H7 and S. aureus. S. aureus cells were slightly more resistant than E.coli O157:H7 cells. The results related to the effect of initial cell concentration of E. coli O157:H7 on the PEF inactivation showed that more inactivation was obtained by decreasing initial cell concentration. Any possible injury by PEF was also investigated after applying 20 kV/cm electric field to the microorganisms. As a result, it was determined that there was 35.92 to 43.36% injury in E. coli O157:H7 cells, and 17.26 to 30.86% injury in S. aureus cells depending on pulse number. The inactivation results were also described by a kinetic model.  相似文献   

7.
In order to obtain sensitive measurements on the synthesis of opsonins following immunization with live or killed S. aureus vaccines, lymph was collected from the efferent popliteal lymphatic duct of sheep during the early phase of the immune response. Lymph and blood serum were assayed for opsonizing capacity using 3H-labeled S. aureus. Within 1 hr after vaccination there was a rapid, transitory decrease in uptake by neutrophils of bacteria opsonized with lymph from sheep given the killed vaccine (Group 2). These results were in contrast to the relatively constant uptake rates of bacteria opsonized with lymph from sheep given the live vaccine (Group 1) and non-vaccinated controls (Group 3) at this time. At 72, 96, and 120 hr post-injection mean uptake values for bacteria opsonized with lymph from either vaccinated group were significantly greater than comparable values for controls. Mean uptakes for organisms opsonized with blood serum from Group 1 at 72 and 96 hr post-injection were significantly greater than comparable values for the control group. The percentage of viable neutrophil-associated bacteria decreased when lymph collected from animals in Group 2 in the first hour post-injection was used to opsonize the organisms. Percentages of viable, neutrophil-associated S. aureus for assays in which blood serum was used to opsonize remained relatively constant at around 45% for Groups 2 and 3. In contrast, however, values of viable neutrophil-associated bacteria for Group 1 decreased during the 120 hr after immunization.  相似文献   

8.
The photodynamic effects of deuteroporphyrin (DT) on the growth and viability ofStaphylococcus aureus, Streptococcus faecalis, andBacillus cereus are described. By exposure to light and DT, the growth ofSta. aureus andStr. Faecalis strains was markedly inhibited, whereasB. cereus was undergoing lysis. Counting the viable bacteria during the DT treatment revealed that more than 99% of the initial bacterial population was killed within the first 30 min of treatment. The pH dependence of the photodynamic inhibitory effect shows that it is best obtained at pH 6.5. No temperature dependence in the range of 37°–44°C could be detected. The best photodynamic effect was achieved when the culture was in the mid-log phase. DT-treated bacteria, when grown in the dark or in the presence of horse serum albumin, were unaffected by the porphyrin action. Electron microscopic examinations ofSta. aureus andStr. faecalis showed the appearance of well-developed mesosomes within the cell cytoplasm.B. cereus preparations have not shown any mesosome formation but showed some lysed cells as well as some spores. None of the mentioned effects by DT and light could be observed on Gramnegative bacteria such asEscherchia coli orPseudomonas aeruginosa.  相似文献   

9.
Intratumoral growth of Staphylococcus aureus Cowan I-derived AP332 was examined by subcutaneous inoculation of cocci in doses ranging from 18 to 1.8 × 105 CFU with Ehrlich ascites tumor cells. Inoculation of 18 CFU AP332 resulted in staphylococcal growth in one of five mice, and the proportion of mice established intratumoral infection increased with the initial inocula. Six other strains of S. aureus also grew in the tumor tissue, and none of the three strains of coagulase-negative staphylococci grew at all. Ethanol-killed tumor cells did not promote staphylococcal growth as vigorously as the live tumor cells, especially when the initial inoculum of AP332 was smaller than 104 CFU.  相似文献   

10.
Filifactor alocis is a newly appreciated pathogen in periodontal diseases. Neutrophils are the predominant innate immune cell in the gingival crevice. In this study, we examined modulation of human neutrophil antimicrobial functions by F. alocis. Both non‐opsonised and serum‐opsonised F. alocis were engulfed by neutrophils but were not efficiently eliminated. Challenge of neutrophils with either non‐opsonised or serum‐opsonised F. alocis induced a minimal intracellular as well as extracellular respiratory burst response compared to opsonised Staphylococcus aureus and fMLF, respectively. However, pretreatment or simultaneous challenge of neutrophils with F. alocis did not affect the subsequent oxidative response to a particulate stimulus, suggesting that the inability to trigger the respiratory response was only localised to F. alocis phagosomes. In addition, although neutrophils engulfed live or heat‐killed F. alocis with the same efficiency, heat‐killed F. alocis elicited a higher intracellular respiratory burst response compared to viable organisms, along with decreased surface expression of CD35, a marker of secretory vesicles. F. alocis phagosomes remained immature by delayed and reduced recruitment of specific and azurophil granules, respectively. These results suggest that F. alocis withstands neutrophil antimicrobial responses by preventing intracellular ROS production, along with specific and azurophil granule recruitment to the bacterial phagosome.  相似文献   

11.
Three methods for the estimation of opsonic activity in the sera of newborn children were tested. Two of them, based on the phagocytosis of opsonised bacteria labelled with radioactive phosphorus32P as measured byin vivo blood clearance or uptake of bacteria in perfused isolated liver, were found to be unsuitable for long term dynamic study mainly because they do not permit the testing of series of samples. The third method (using isolated phagocytic cellsin vitro) permits the differentiation of the opsonic effect of complement and antibody and, furthermore, the firmness of the bond between microbes and phagocytes (which reflects the degree of opsonization) can be established. It was found that a 2-mercaptoethanol-resistant antibody, probably of the IgG type, was responsible for the opsonic activity of children's sera toEscherichia coli 083. Homologous antibody (toEscherichia coli 083) could be differentiated from beterologous antibody (toEscherichia coli 086) using the opsonic test only at low dilutions of sera. The combination of newborn piglet complement and antibody of children's sera yielded higher values of opsonic activity than either component separately.  相似文献   

12.
TheEscherichia coli O73:K92:H1 serotype, which possesses a capsular antigen immunochemically similar to the capsule of the group C meningococcus, is demonstrated in this study to be resistant to phagocytosis by normal human PMNs and serum and to be dependent upon immune antibody and presumably the classical complement pathway for opsonization. Using both a luminol-dependent chemiluminescence assay and an in vitro bactericidal system, we examined, in both the absence and presence of complement, the opsonic activity of IgM ang IgG antisera. Of the various antisera tested, only those sera cross-reactive with the K92 capsular antigen were found to be opsonic both in vivo and in vitro, while somatic O or lipid A antisera demonstrated no activity. In in vitro studies with capsular IgM and IgG antisera, only IgG demonstrated opsonic activity without complement, whereas IgM required complement for opsonization of O73:K92:H1. These data demonstrate that antisera directed toward capsular antigens are opsonic for this phagocytosis-resistantE. coli, and that complement is a necessity for opsonization in the absence of sufficient capsular IgG antibodies.  相似文献   

13.
We examined the serum requirements for surface phagocytosis of Staphylococcus epidermidis and Escherichia coli and for the subsequent chemiluminescent response of human neutrophils. Substantial surface phagocytosis of S. epidermidis occurred in the absence of opsonins, although the presence of 10% pooled or heat-inactivated serum significantly increased phagocytosis. There was no significant difference between these opsonins, indicating that surface phagocytosis of S. epidermidis did not require complement. Unopsonized E. coli were not as readily phagocytized as S. epidermidis (33% versus 57%). In contrast to S. epidermidis optimal phagocytosis of E. coli required complement as 10% heat inactivated donor serum (HHS) was significantly less effective as an opsonin than 10% pooled healthy donor serum (PHS). The time kinetics for phagocytosis of each organism were similar, with most of the phagocytosis occurring in the first 10 min. The chemiluminescent response of neutrophils produced discrepant results. Maximal chemiluminescence was observed when neutrophils were stimulated with bacteria opsonized in PHS. The response to HHS-opsonized bacteria was less, and chemiluminescence to unopsonized bacteria was only marginally higher than the control, even though there was relatively good phagocytosis. These results define the opsonic requirements for surface phagocytosis of S. epidermidis and E. coli and indicate that although complement may not be required for phagocytosis, it is necessary for generation of a maximal oxidative burst, and thus may be essential for efficient intracellular killing.  相似文献   

14.
《Epigenetics》2013,8(5):492-501
Mastitis is a multietiological complex disease, defined as inflammation of parenchyma of mammary glands. Bacterial infection is the predominant cause of mastitis, though fungal, viral and mycoplasma infections also have been reported. Based on the severity of the disease, mastitis can be classified into subclinical, clinical and chronic forms. Bacterial pathogens from fresh cow milk were isolated and classified by standard microbiological tests and multiplex PCR. Epidemiological studies have shown that Escherichia coli is the second largest mastitis pathogen after Staphylococcus aureus in India. Based on Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR profile and presence of virulence genes, a field isolate of E. coli was used for intramammary inoculation in lactating mice. Histopathological examination of hematoxylin and eosin stained sections showed severe infiltration of polymorphonuclear neutrophils, mononuclear inflammatory cells in the alveolar lumen and also in interstitial space, and necrosis of alveolar epithelial cells after 24 h. Western blot and immunohistochemical analysis of mice mammary tissues showed significant hyperacetylation at histone H3K14 residue of both mammary epithelial cells and migrated inflammatory cells. Quantitative real-time PCR and genome-wide gene expression profile in E. coli infected mice mammary tissue revealed differential expression of genes related to inflammation, immunity, antimicrobial peptide expression, acute phase response and oxidative stress response. Expression of milk proteins was also suppressed. ChIP assay from paraffinized tissues showed selective enrichment of acetylated histone H3K14 and H4K8 at the promoters of overexpressed genes. These data suggest that E. coli infection in mice mammary tissue leads to histone hyperacetylation at the promoter of immune genes, which is a pre-requisite for the expression of inflammatory genes in order to mount a drastic immune response.  相似文献   

15.
Abstract We examined the serum requirements for surface phagocytosis of Staphylococcus epidermidis and Eschericia coli and for the subsequent chemiluminescent response of human neutrophils. Substantial surface phagocytosis of S. epidermidis occured in the absence of opsonins, although the presence of 10% pooled or heat-inactivated serum significantly increased phagocytosis. There was no significant difference between these opsonins, indicating that surface phagocytosis of S. epidermidis did not require complement, Unopsonized E. coli were not as readily phagocytized as S. epidermidis (33% versus 57%). In contrast to S. epidermidis optimal phagocytosis of E. coli required complement as 10% heat inactivated donor serum (HHS) was significantly less effective as an opsonin than 10% pooled healthy donor serum (PHS). The time kinetics for phagocytosis of each organism were similar, with most of the phagocytosis iluminescent response of neutrophils produced discrepant results. Maximal chemiluminescence was observed when neutrophils were stimulated with bacteria opsonized in PHS. The response to HHS-opsonized bacteria was less, and chemiluminescence to unopsonized bacteria was only marginally higher than the control, even though there was relatively good phagocytosis. These results define the opsonic requirements for surface phagocytosis of S. epidermidis and E. coli and indicate that although complement may not be required for phagocytosis, it is necessary for generation of a maximal oxidative burst, and thus may be essential for efficient intracellular killing.  相似文献   

16.
Methicillin resistant Staphylococcus aureus (MRSA) is an opportunistic pathogen found in hospital and community environments that can cause serious infections. A major barrier to genetic manipulations of clinical isolates has been the considerable difficulty in transforming these strains with foreign plasmids, such as those from E. coli, in part due to the type I and IV Restriction Modification (R-M) barriers. Here we combine a Plasmid Artificial Modification (PAM) system with DC10B E. coli cells (dcm mutants) to bypass the barriers of both type I and IV R-M of S. aureus, thus allowing E. coli plasmid DNA to be transformed directly into clinical MRSA strains MW2, N315 and LAC, representing three of the most common clonal complexes. Successful transformation of clinical S. aureus isolates with E. coli-derived plasmids should greatly increase the ability to genetically modify relevant S. aureus strains and advance our understanding of S. aureus pathogenesis.  相似文献   

17.
An enzyme was identified in human serum which unlike lysozyme cleaved the amide bond between N-acetyl-muramic acid and l-alanine of the peptide side chain of the rigid layer (murein) of Escherichia coli. The N-acetylmuramyl-l-alanine amidase released all of the peptide side chains including those to which the lipoprotein is bound. A portion of the peptide side chains of the Micrococcus lysodeikticus murein was also hydrolysed from the polysaccharide chains. E. coli, M. lysodeikticus, Bacillus subtilis and Staphylococcus aureus were not killed by the amidase. Treatment of E. coli with EDTA or osmotic shock rendered the cells sensitive to the amidase and they were killed. Possible biological functions of the amidase are discussed.The enzyme was separated from lysozyme in human serum. Gel permeation chromatography indicated a molecular weight of the active enzyme of 82,000 while gel electrophoresis in the presence of sodium dodecyl sulfate revealed a molecular weight of 75,000. Thus, the enzyme probably consists of a single polypeptide chain. Incubation with neuraminidase rendered the amidase more basic suggesting the release of sialic acid residues. The modified glycoprotein disclosed an increased activity to murein. Enzyme activity was inhibited by p-chloromercuribenzene sulfonate and ethyleneglycol-bis(2-aminomethyl) tetraacetate (EGTA) at 1 and 0.2 mM concentration, respectively, whereas EDTA up to 5 mM was without effect. The amidase was also inactivated by agents that reduce disulfide bridges.  相似文献   

18.

Objectives

Our current understanding of hormone regulation in lung parenchyma is quite limited. We aimed to quantify a diverse array of biologically relevant protein mediators in alveolar lining fluid (ALF), compared to serum concentrations, and explore factors associated with protein compartmentalization on either side of the air-blood barrier.

Research Design and Methods

Participants were 24 healthy adult non-smoker volunteers without respiratory symptoms or significant medical conditions, with normal lung exams and office spirometry. Cell-free bronchoalveolar lavage fluid and serum were analyzed for 24 proteins (including enteric and metabolic hormones, apolipoproteins, adipokines, and cytokines) using a highly sensitive multiplex ELISA. Measurements were normalized to ALF concentrations. The ALF:serum concentration ratios were examined in relation to measures of protein size, hydrophobicity, charge, and to participant clinical and spirometric values.

Results

ALF measurements from 24 individuals detected 19 proteins, including adiponectin, adipsin, apoA-I, apoA-II, apoB, apoC-II, apoC-III, apoE, C-reactive protein, ghrelin, glucose-dependent insulinotropic peptide (GIP), glucagon-like peptide-1 (GLP-1), glucagon, insulin, leptin, monocyte chemoattractant protein-1, plasminogen activator inhibitor-1, resistin, and visfatin. C-peptide and serpin E1 were not detected in ALF for any individual, and IL-6, IL-10, and TNF-alpha were not detected in either ALF or serum for any individual. In general, ALF levels were similar or lower in concentration for most proteins compared to serum. However, ghrelin, resistin, insulin, visfatin and GLP-1 had ALF concentrations significantly higher compared to serum. Importantly, elevated ALF:serum ratios of ghrelin, visfatin and resistin correlated with protein net charge and isoelectric point, but not with molecular weight or hydrophobicity.

Conclusions

Biologically relevant enteric and metabolic hormones, apolipoproteins, adipokines, and cytokines can be detected in the ALF of healthy individuals. For the proteins measured, charge may influence trafficking and compartmentalization to the alveolar airspace more than molecular weight or hydrophobicity. These data may have implications for homeostasis and drug delivery to the lung.  相似文献   

19.
The purpose of this study was to determine the inhibitory effects of cranberry juice on pathogenic microorganisms. The microorganisms analyzed were Escherichia coli from patients with urinary infections, Salmonella spp., Listeria monocytogenes, Pseudomona aeruginosa, and Staphylococcus aureus. The disc method was used to determine the sensitivity of bacteria to cranberry juice (CJ, both concentrated and diluted). A lawn of 106 cfu/ml was grown on agar surfaces in Petri dishes and on Whatman discs that had been previously saturated with CJ and CJ : water. 1 : 1 to 1 : 50 juice solutions had been placed on the discs, which were cultured and incubated. The results indicated that S. aureus was more susceptible to cranberry juice inhibition than the other microorganisms. L. monocytogenes was the most resistant to the inhibitory action of cranberry juice, showing a significant difference from the inhibition of P. aeruginosa, uropathogenic E. coli, Salmonella spp., and S. aureus. This study also demonstrated that the inhibitory activity of cranberry juice for E. coli took place up to a dilution of 1 : 20. Published in Russian in Prikladnaya Biokhimiya i Mikrobiologiya, 2008, Vol. 44, No. 3, pp. 333–336. The text was submitted by the authors in English.  相似文献   

20.
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