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1.
Brucella organisms are pathogens that ultimate goal is to propagate in their preferred niche, the cell. Upon cell contact the bacteria is internalized via receptor molecules by activating small GTPases of the Rho subfamily and by a moderate recruitment of actin filaments. Once inside cells, Brucella localizes in early phagosomes, where it avoids fusion with late endosomes and lysosomes. These early events require the control of Rab small GTPases, and cytokines such as the G-CSF. Then, the bacterium redirects its trafficking to autophagosomes and finally reaches the endoplasmic reticulum, where it extensively replicates. Some of the bacterial molecular determinants involved in the internalization and early events after ingestion are controlled by the BvrS/BvrR two component regulatory system, whereas the intracellular trafficking beyond this early compartments are controlled by the VirB type IV secretion system. Once inside the endoplasmic reticulum, Brucella extensively replicates without restricting basic cellular functions or inducing obvious damage to cells. The integrity of Brucella LPS on the bacterial surface is one of the required factors for Brucella intracellular survival, and therefore for virulence. 相似文献
2.
AIM: To investigate the interaction of polymorphisms of intercellular adhesion molecule-1 (ICAM-1) gene K469E and monocyte chemoattractant protein-1 (MCP-1) gene -2518A/G in the invasion and metastasis of gastric carcinoma. METHODS: Based on TNM classification, 4 500 patients with confirmed gastric carcinoma from the First Affiliated Hospital of Xinxiang Medical University in China from December 2009 to November 2014 were divided into stageⅠ group, stage Ⅱgroup, stage Ⅲ group, stage Ⅳ group, and stage 0 group, with 900 cases in each group. No significant difference among the 5 groups in age, gender, ethnicity, birthplace and living habit was observed. The genetic polymorphisms of ICAM-1 gene K469E and MCP-1 gene -2518A/G were analyzed by the technique of polymorphism-polymerase chain reaction (PCR) in peripheral blood leukocytes of above-mentioned cases. RESULTS: Statistical tests showed signi-ficant differences in the frequencies of K469E (EE) and -2518A/G (GG) among each group (P<0.01). The risk of the invasion and metastasis of gastric carcinoma significantly increased in subjects with K469E (EE) genotype and in those with -2518A/G (GG) genotype. Combined analysis of the polymorphisms showed that distribution frequency of K469E (EE)/-2518A/G (GG) in stage Ⅰ group, stage Ⅱ group, stage Ⅲ group, stage Ⅳ group and stage 0 group was 39.22%, 53.22%, 59.22, 65.44% and 12.11%, respectively (P<0.01). The people who carried with K469E (EE)/-2518A/G (GG) had a high risk of the invasion and metastasis of gastric carcinoma, and statistical analysis suggested a positive interaction in a super-multiplicative model between K469E (EE) and -2518A/G (GG) in increasing the risk of the invasion and metastasis of gastric carcinoma. CONCLUSION: ICAM-1 gene K469E (EE) and MCP-1 gene -2518A/G (GG) are the risk factors in the invasion and metastasis of gastric carcinoma, and significant interactions between genetic polymorphisms of K469E and -2518A/G added the risk of the invasion and metastasis of gastric carcinoma. 相似文献
3.
家蚕蛾油对蛹虫草液体发酵培养的影响 总被引：1，自引：0，他引：1
通过对蛹虫草菌丝体干产量以及胞外高分子聚合物和胞内多糖含量的测量分析,研究了添加家蚕蛾油对蛹虫草(Cordyceps militarisL.)液体发酵培养效果的影响。添加4%雄蚕蛾油或2%雌蚕蛾油,蛹虫草菌丝体的产量分别增加76.1%和45.9%,胞外高分子聚合物含量分别增加64.2%和43.0%,均达到最大值;添加3%雄蚕蛾油或雌蚕蛾油使胞内多糖含量分别增加46.8%和47.1%,菌丝体产量分别增加145%和102%,均达到最大值。结果表明,添加一定量的家蚕蛾油对蛹虫草液体发酵培养具有促进作用,而在作用效果上,家蚕雄蛾油要优于家蚕雌蛾油。 相似文献
4.
Balázs Jóri Dóra Szeg? Zoltán Szigeti Demeter Lásztity 《Pesticide biochemistry and physiology》2007,88(1):57-65
Paraquat (Pq) inducible transporters are presumed to play a role in the resistance mechanism of horseweed and to function by carrying paraquat to a metabolically inactive compartment. The uptake and intracellular localisation of paraquat, the effect of transporter inhibitors on resistance, and paraquat-induced gene expression were studied to obtain a better understanding of the mechanism of resistance. Investigations proved that paraquat entered the cells of both resistant and susceptible biotypes, approached the maximum within the first hour in chloroplasts, and then declined in all organelle fractions. In the resistant biotype paraquat was located in the vacuoles a day after treatment. Selective transporter inhibitors blocked the sequestration of paraquat, suggesting the participation of not directly energized transporters. Four EST fragments were identified that were expressed in response to paraquat. Two of them are thought to play a role in the general stress response (Ferr2, Myb). The others exhibit a similarity to transporters (EmrE, CAT) and could conceivably be involved in the intracellular transport of paraquat and the mechanism of resistance. 相似文献
5.
A. Dowling J. C. Hodgson M. P. Dagleish P. D. Eckersall J. Sales 《Veterinary immunology and immunopathology》2004,100(3-4):197
Pneumonic pasteurellosis is a common respiratory infection in cattle that has major economic and welfare implications world-wide and the incidence in the UK due to Pasteurella multocida, currently the same as that associated with Mannheimia haemolytica, is increasing. Whereas much is known regarding the pathogenesis of M. haemolytica infections little information is available on the pathogenic process of pasteurellosis initiated by P. multocida. In the present work calf systemic and innate immune responses to intratracheal challenge with formalin-killed P. multocida biotype A:3 and to subsequent experimental lung infection with live P. multocida were investigated. Eight-week-old calves were challenged intratracheally on day 0 with either 109 colony forming units (cfu) of formalin-killed P. multocida biotype A:3 in 300 ml saline (n=10) or 300 ml saline alone (n=10), followed, at day 21, by challenge with 109 cfu live P. multocida. Pathophysiological and lung phagocyte responses were assessed by clinical monitoring, sequential lung lavage and blood sampling. Results for samples obtained before, during and after challenge showed clinical and acute phase protein responses to both bacterial culture and saline control treatments, although higher responses were associated with bacterial challenge. Phagocytosis of P. multocida during 1 h incubation periods with lavaged cells in vitro was unaffected by exposure in vivo to killed P. multocida and there was evidence that P. multocida was able to survive intracellularly during this assay. There was no indication that lung exposure to formalin-killed P. multocida conferred protection against subsequent homologous live challenge. 相似文献
6.
AIM:To study the effect of salvia miltiorrhiza (SM) on cell contraction and intracellular calcium of enzymatically isolated rat ventricular myocytes during normoxia and anoxia/reoxygenation.METHODS:Contraction and intracel ular calcium were determined with video tracking system and spectrofluorometric method,and the chemical anoxic method was employed. RESULTS:The ±dL/dtmax, dL of cell contraction and the amplitude of [Ca2+]i in the cardiomyocytes following SM treatment were decreased in a dose-dependent manner. During anoxia, the ±dL/dtmax, dL and amplitude of [Ca2+]i were decreased, while the diastolic Ca2+ level was elevated compared with control group. All the contractile parameters and the diastolic Ca2+ level were back toward pretreatment values during reoxygenation, but could not return to control level. After the treatment with SM (3 g/L), ±dL/dtmax and dL of cell contraction and the amplitude of [Ca2+]i were higher and the diastolic Ca2+ level was lower than those in anoxia/reoxygenation group. CONCLUSION:SM antagonized effects of anoxia and reoxygenation on cell contraction and intracellular calcium in isolated ventricular myocytes. 相似文献
7.
AIM: To observe the influence of erythropoietin (EPO) on eryptosis and production of reactive oxygen species (ROS) in erythrocytes under stimulation of hydrogen peroxide (H2O2),and to explore its related mechanism. METHODS: The erythrocyte suspension (1%) was cultured in vitro and divided into 3 groups:control group (C group, the culture medium was PBS), H2O2 group (H group, the culture medium was PBS containing H2O2 at final concentration of 100 μmol/L) and EPO group (E group, the culture medium was PBS containing H2O2 at final concentration of 100 μmol/L and EPO at final concentration of 2×104 U/L). The erythrocytes were collected at 24 h and 60 h. The eryptosis was detected by flow cytometry with Annexin V staining. The production of ROS and intracellular calcium ion concentration ([Ca2+]i) were also analyzed by flow cytometry. RESULTS: The eryptosis in C group was increased as the incubating time extended. The eryptosis in H group was higher than that in C group (P<0.01), while that in E group was lower than that in H group (P<0.01). Meanwhile, ROS production and[Ca2+]i were higher in H group than those in C group (P<0.01), but those were lower in E group than those in H group (P<0.05 or P<0.01). CONCLUSION: EPO inhibits eryptosis induced by H2O2 and its mechanism may be related to antioxidant effect and change of[Ca2+]i. 相似文献
8.
Dowling A Hodgson JC Dagleish MP Eckersall PD Sales J 《Veterinary immunology and immunopathology》2004,100(3-4):197-207
Pneumonic pasteurellosis is a common respiratory infection in cattle that has major economic and welfare implications world-wide and the incidence in the UK due to Pasteurella multocida, currently the same as that associated with Mannheimia haemolytica, is increasing. Whereas much is known regarding the pathogenesis of M. haemolytica infections little information is available on the pathogenic process of pasteurellosis initiated by P. multocida. In the present work calf systemic and innate immune responses to intratracheal challenge with formalin-killed P. multocida biotype A:3 and to subsequent experimental lung infection with live P. multocida were investigated. Eight-week-old calves were challenged intratracheally on day 0 with either 109 colony forming units (cfu) of formalin-killed P. multocida biotype A:3 in 300 ml saline (n=10) or 300 ml saline alone (n=10), followed, at day 21, by challenge with 109 cfu live P. multocida. Pathophysiological and lung phagocyte responses were assessed by clinical monitoring, sequential lung lavage and blood sampling. Results for samples obtained before, during and after challenge showed clinical and acute phase protein responses to both bacterial culture and saline control treatments, although higher responses were associated with bacterial challenge. Phagocytosis of P. multocida during 1 h incubation periods with lavaged cells in vitro was unaffected by exposure in vivo to killed P. multocida and there was evidence that P. multocida was able to survive intracellularly during this assay. There was no indication that lung exposure to formalin-killed P. multocida conferred protection against subsequent homologous live challenge. 相似文献
9.
AIM：To investigate the effects of substance P (SP) on the modulation of H+-gated current in neurons. METHODS：Whole-cell patch-clamp technique was used to record the H+-gated current in the acutely isolated rat dorsal root ganglion (DRG) neurons at pH 4.0, pH 5.0, pH 6.0, and both SP and H+. The modulating action of SP on H+-gated current in the acutely isolated rat DRG neurons was studied by intracellular dialysis. RESULTS：H+-gated currents recorded at pH 5.0 were divided into 4 types: transient inward (T-type),sustained inward (S-type),biphasic inward (B-type) and opposite (O-type). SP exhibited obvious enhancing effect on the sustained component of S-type and B-type H+-gated currents, and the enhancing current amplitude was (85.53±22.93)%. However, the enhancing effect was not blocked by the SP receptor NK1 antagonist in about 81.8% DRG neurons. The enhancing effect was blocked by nonpeptidic SP receptor antagonist in about 75% DRG neurons. SP also exhibited obvious inhibitory effect on the sustained component of S-type and B-type H+-gated currents, and the inhibitory current amplitude was (48.46±4.45)%. However, the inhibitory effect was not blocked by the SP receptor antagonist in about 88.9% DRG neurons. After intracellular dialysis, GDP-β-S could not block the modulating action of SP on H+-gated currents. CONCLUSION：There are 4 types of H+-gated currents in acutely isolated rat DRG neurons: T-type, S-type, B-type and O-type. The modulating action of SP on H+-gated current exhibits both enhancement and inhibition. The regulatory mechanism includes G-protein-coupled receptor pathway and the binding of SP to a locus of H+-gated ion channels to exert modulating action on the H+-gated current. 相似文献
10.
G. Pietramellara J. Ascher F. Borgogni M. T. Ceccherini G. Guerri P. Nannipieri 《Biology and Fertility of Soils》2009,45(3):219-235
The review discusses origin, state and function of extracellular DNA in soils and sediments. Extracellular DNA can be released
from prokaryotic and eukaryotic cells and can be protected against nuclease degradation by its adsorption on soil colloids
and sand particles. Laboratory experiments have shown that DNA adsorbed by colloids and sand particles can be taken up by
prokaryotic competent cells and be involved in natural transformation. Most of these experiments have been carried out under
artificial conditions with pure DNA molecules and pure adsorbing matrices, but in soils and sediments, pure surface-reactive
colloids are not present and DNA is present with other cellular components (wall debris, proteins, lipids, RNA, etc.) especially
if released after cell lysis. The presence of inorganic compounds and organic molecules on both soil particles and DNA molecules
can influence the DNA adsorption, degradation and transformation of competent cells. Extracellular DNA can be used as C, N
and P sources by heterotrophic microorganisms and plays a significant role in bacterial biofilm formation. The nucleotides
and nucleosides originated from the degradation of extracellular DNA can be re-assimilated by soil microorganisms. Extracellular
DNA in soil can be leached and moved by water through the soil profile by capillarity. In this way, the extracellular DNA
secreted by a cell can reach a competent bacterial cell far from the donor cell. Finally, the characterisation of extracellular
DNA can integrate information on the composition of the microbial community of soil and sediments obtained by analysing intracellular
DNA. 相似文献