جستجوی مقالات مرتبط با کلیدواژه « LPS » در نشریات گروه « زیست شناسی »

Background &

Increasing antibiotic resistance in Acinetobacter baumannii isolates has become a major global concern today. The mechanism of the food supply through iron supply through Siderophores is one of the most important factors in the adaptation of bacteria to adverse conditions. The study of the frequency of the presence of Siderophore genes in clinical isolates      provides a high understanding of the mechanism of bacterial resistance. Therefore, in this study, we investigated the frequency of antibiotic resistance in isolates containing the Siderophore gene.Materials &

Clinical samples were collected from hospitalized patients includingrespiratory, wound, urinary, and blood samples. Biochemical tests were performed to isolate the    bacteria. A molecular sensitive polymerase chain reaction (PCR) test was performed to confirm  Acinetobacter baumannii strains and to evaluate the presence of target genes. Microbial susceptibility testing was performed by disk diffusion method according to CLSI instructions and the relationship between microbial resistance and expression of Siderophore genes in isolates was investigated.

According to PCR results, out of 64 isolates identified by biochemical tests, 28 isolates (43.75%) were identified as Acinetobacter baumannii. All 28 isolated isolates (100%) had LPS genes and 15 isolates (53.57%) had Siderophore gene with 93.3% resistance to Carbapenems and 26.6% to Colistin sulfate and antibiotics. Were identified as XDR and MDR strains.

Antibiotic resistance and the prevalence of Siderophore and LPS genes in               Acinetobacter baumannii strains are worrisome and require infection control measures including management of antibiotics and rapid identification of resistant isolates.

common microbial pathogens with antibiotic resistance in causing respiratory infections in patients admitted to the ICU. Making a vaccine can be one of the effective ways to combat this infection. This study was performed to evaluate the protective effects of PLGA nanoparticles containing detoxified lipopolysaccharide (D-LPS) of Acinetobacter baumannii as a vaccine in mouse lung infection. Müller Hinton Broth culture medium was used for mass propagation of bacteria. Bacterial LPS was extracted by hot water-phenol method and detoxified with 0.2M NaOH. Encapsulation of detoxified LPS in PLGA particles was performed by Double emulsion solvent evaporation (Water/Oil/Water emulsion). The prepared particles were between 150 and 200 nm in diameter with a negative surface charge. Forty Balb/C mice were randomly divided into four groups of 10 (control, PLGA-receiving group, D-LPS-receiving group, and PLGA-D-LPS-receiving group). All groups were vaccinated three times at intervals of 14 days. On day 35, live bacteria were delivered to the groups through the lungs, and after 48 hours, the mice’s lungs were removed for bacteriological and histopathological studies. Culture of homogenized extract of lung tissue showed a significant difference between group 4 and other groups. (P <0.05) Histological study also showed the protective effect of PLGA nanoparticles containing detoxified LPS. This study showed that PLGA particles containing detoxified LPS of Acinetobacter baumannii were successful in stimulating the immune system of mice and could be used as a vaccine..

Pseudomonas aeruginosa is a particular importance due to the numerous factors of pathogenicity and the prevalence of multi-resistance strains throughout the world. Therefore, the need to prevent and produce an effective vaccine seems necessary. The aim of this study was to use PLGA nanoparticles in the design of vaccine with alginate antigens, lipopolysaccharide, and exotoxin, A Pseudomonas aeruginosa. In this study, strain PAO1 of Pseudomonas aeruginosa is used. Then, antigens including, alginate, lipopolysaccharide, and exotoxin A were extracted. Then, lipopolysaccharide was detoxified by hot phenol method. Exotoxin A was purified by chromatography and detoxified with formalin. Then, antigens separately conjugated to PLGA. FT-IR and AFM methods were usedto confirm conjugation with nanoparticles. A rabbit model was used to study the pyrogenic effects of conjugates. The mortality effect of conjugates on mouse model was tested.
The success of conjugation based on the size and charge of the nanoparticle was confirmed. The presence of antigenic functional groups in the structure of the nanoparticle and the formation of a steric bond confirmed with FT-IR results and the corresponding courier form.
The 3D conjugate images of nanoparticles before and after conjugation showed an increase in the height of nanoparticle binding sites. The change from initial sharpness to puff after the conjugation confirmed the success of conjugation. Failure to observe the pyrogenic effects in the rabbit and no mortality observed in mice was proved.
Discussion and All of the results showed that conjugates were effective in immunization. Therefore, it can be a candidate vaccine with a great potential against Pseudomonas causing diseases

Aim: The aim of the current study was to isolate microglial cells from neonatal rat brain, activate the cells using lipopolysaccharide (LPS) and examine the effect of the inflammatory factors that they express on dopaminergic (DAergic) neurons.
mixed glial cells were isolated from 1-3 day rat neonatal brains and then microglial cells were extracted from them. Upon treatment of the cells with LPS, their conditioned media (CM) were collected. DAergic SH-SY5Y cell line was seeded in 96-well plates and fed with the collected CM. The rate of viability and apoptosis of the neuronal cells was examined using MTT and apoptosis tests and the data were analyzed statistically.
Ten to thirteen days after isolation, mixed glial cells were composed of three types: astroglia, oligodendrocytes and microglia. Microglia were floating while semi-attached to the surface. Twenty four hours post-isolation, these cells were transferred to and cultured in separate dishes where they formed spindled and ramified phenotypes. At this stage, the cells were treated with LPS to be activated. This activation was demonstrated by morphological changes from spindle-like form to amoeboid form, detection of increase in NO expression using Griess test and induction of inflammatory iNOS and TNF-α gene expression. Also teatment of SH-SY5Y cell line with conditioned medium of activated microglia led to both apoptotic and necrotic cell death.
LPS-mediated activation of microglia results in overexpression of neuroinflammatory markers. The overproduction of these markers results in both apoptotic and necrotic cell death amongst DAergic neurons via neuroinflammation.

Microglial cells are the smallest glial cells in the central nervous system (CNS) which، as brain macrophages have an important role in regulation of innate immunity. Quick phenotypic changes of these cells from quiescent state to activated shape and secretion of diffusible factors، show their unique ability in response to inflammatory stimuli. Nitric oxide (NO)، a free radical، is one of the molecules which produce by activated microglial cells and have a pivotal role in progression of neurodegenerative disorders like Parkinson Disease (PD) and Alzheimer Disease (AD). Therefore، Restrain the overactivation of microglial cells، is a chief strategy to decrease neurotoxic damages which threat central nervous system. In this research we investigate the ability of «IMOD» as an herbal drug، to decrease the bacterial lipopolysaccharide (LPS) - induced NO production in newborn rat brains. The production of NO was assessed by Griess assay whilst the cell viability was determined by MTT assay. Results show that high dilutions of this drug have an anti-inflammatory effect on microglial cells، which is able to decrease the amount of produced NO in these cells. With these results we can use IMOD to decrease neurological damages in neurodegenerative disorders due to microglial activation.

Heat shock proteins (HSPs) inhibit production of pro- inflammatory cytokines. Carbenoxolone is regarded to induce the production of HSPs. The aim of this study was the evaluation of the effect of Carbenoxolone in reduction of the severity of systemic inflammation induced by LPS in a murine model. %80 lethal dose of LPS was determined in balb/C mice، also appropriate dose of drug for efficient reduction in mortality was determined. LPS+D-GalN with drug were injected to different groups، in different times، after 24 hours the mortality rate was calculated and the severity of necrosis measured in the kidney and livers of the survived mice. After 3 hours serum samples were collected and the concentrations of TNF-α were measured in each group. Administration of Carbenoxolone with LPS reduced the lethality rate from 80 to %20. The severity of necrosis in the liver and kidney of drug administrated groups decreased significantly in comparison with the positive control group. The concentration of TNF-α in mice received LPS increased significantly in comparison with the control group (P=0. 032)، but in drug received groups no significant differences were seen with respect to the control. Discussion and Carbenoxolone significantly reduced the severity and damage due to endotoxic shock.