جستجوی مقالات مرتبط با کلیدواژه « serratia marcescens » در نشریات گروه « پزشکی »

17 β- estradiol (E2) is an important pollutant of the aquatic system. It is responsible for sexual disruptions in the majority of aquatic organisms. This study aimed to search for bacteria with high potential degradation of E2 as an important method for bioremediation.

Sewage water samples were collected and treated to isolate bacterial strains which were identified by conventional methods and 16S ribosomal RNA gene sequence analysis. The biodegradation of E2 by the isolated strains was evaluated under different environmental conditions.

Two bacterial strains were recovered from sewage water samples and identified as Stenotrophomonas tumulicola and Serratia marcescens, (named ASc2 and ASc5 respectively). Co-culture of the two strains showed biodegradation of approximately 93.6 % of E2 (50 mg. L-1) within 48 hours. However, the biodegradation capacity of the same E2 concentra- tion was 69.4% and 71.2% for ASc2 and ASc5 each alone, respectively. The optimum cultivation conditions for efficient E2 biodegradation by co-culture were 5% (v/v) inoculation volume with 50 mg. L-1 of E2 as the initial concentration at pH 7 and 30°C within 48 hours inoculation period.

This study detected new bacterial strains that are capable of rapid degradation of estrogen as an environmental pollutant.

Serratia marcescens has emerged as a nosocomial pathogen responsible for human infections, where antibiotic resistance further complicates the treatments. In S. marcescens, biofilm formation and virulence factor production are controlled via quorum sensing (QS) system. QS is a signaling system that enables gene regulation to control diverse physiological functions in bacteria. Essential oils have shown to be potential in diminishing the pathogenicity and virulence of drug-resistant bacteria. This study was performed to determine whether eugenol would affect QS system, biofilm formation and virulence factor production of S. marcescens.

Biofilm formation, extracellular virulence factor production (hemolysin and protease), swarming motility and pigment formation of S. marcescens ATCC 13880 and S. marcescens Sm2 were assessed after eugenol exposure at 1.25 and 2.5 µg/ml concentrations. The expression of genes involved in motility (flhD), attachment (fimC), biofilm formation (bsmB, bsmA), and QS regulatory (swrR) were also evaluated.

Eugenol treatment at 1.25 and 2.5 µg/ml concentrations caused a significant reduction in biofilm formation. The pigment, hemolysin and protease production of two studied S. marcescens strains, also reduced significantly by eugenol treatments (p<0.05). The bsmA, bsmB, flhD and fimC genes were down-regulated after eugenol treatment. The swrR gene expression was also reduced significantly by eugenol in both S. marcescens strains (p<0.05).

Eugenol inhibited quorum sensing-regulated functions of two studied S. marcescens strains.

Serratia marcescens, an opportunistic human pathogen, is reported as an important cause of nosocomial infection and outbreaks. Although the genome of S. marcescens (ATCC 13880) was completely sequenced by 2014, there are no studies on the proteomic profile of the organism. The objective of the present study is to analyze the protein profile of S. marcescens (ATCC 13880) using a high resolution mass spectrometry (MS).

Serratia marcescens ATCC 13880 strain was grown in Luria-Bertani broth and the protein extracted was subjected to trypsin digestion, followed by basic reverse phase liquid chromatography fractionation. The peptide fractions were then analysed using Orbitrap Fusion Mass Spectrometry and the raw MS data were processed in Proteome Discoverer software.

The proteomic analysis identified 15 009 unique peptides mapping to 2541 unique protein groups, which corresponds to approximately 54% of the computationally predicted protein-coding genes. Bioinformatic analysis of these identified proteins showed their involvement in biological processes such as cell wall organization, chaperone-mediated protein folding and ATP binding. Pathway analysis revealed that some of these proteins are associated with bacterial chemotaxis and beta-lactam resistance pathway.

To the best of our knowledge, this is the first high-throughput proteomics study of S. marcescens (ATCC 13880). These novel observations provide a crucial baseline molecular profile of the S. marcescens proteome which will prove to be helpful for the future research in understanding the host-pathogen interactions during infection, elucidating the mechanism of multidrug resistance, and developing novel diagnostic markers or vaccine for the disease.

Serralysin is an extracellular metalloprotease from Serratia marcescens which has been the subject of extensive biological investigations. The goal of this study was to extract and purify serralysin from S. marcescens and to investigate its cytotoxic activity on the colorectal cancer cell line.

The presence of the serralysin gene was confirmed using PCR. The supernatant of bacterial culture was collected and precipitated using ammonium sulfate. The precipitated protein was dialyzed and subjected to ion exchange chromatography for further purification. Casein assay and skim milk assay was used to confirm the enzymatic activity. SDS-PAGE was used to visualize the presence of serralysin. Metalloprotease inhibition activity was performed using 50 mM EDTA. Cytotoxic activity of serralysin was assessed on MTT assay.

The PCR product corresponding to serralysin was estimated to be approximately 1500 bp. A transparent zone around the bacterial colonies on skim milk agar and casein digestion confirmed the proteolytic activity of serralysin. A 52 kDa band in SDS-PAGE corresponding to serralysin was observed before and after purification processes. MTT assay showed IC50 values 24.78 μg/ml and 19.16 μg/ml after 24 h and 48 h exposure of Caco-2 cells to serralysin, respectively.

Our results showed that native serralysin has anticancer potential and may be a candidate for further pharmaceutical research and development. Further in vivo and in vitro mechanistic studies are suggested to confirm the biological activities.

Serratia marcescens, a potentially pathogenic bacterium, benefits from its swarming motility and resistance to antibiotic as two important virulence factors. Inappropriate use of antibiotics often results in drug resistance phenomenon in bacterial population. Use of probiotic bacteria has been recommended as partial replacement. In this study, we investigated the effects of some lactobacilli culture supernatant on swarming, motility and antibiotic resistance of S. marcescens.
Antimicrobial activity of lactobacilli supernatant and susceptibility testing carried out on S. marcescens isolates. Pretreatment effect of lactobacilli culture supernatant on antibiotic - resistance pattern in S. marcescens was determined by comparison of the MIC of bacteria before and after the treatment.
Our results showed that pretreatment with L. acidophilus ATCC 4356 supernatant can affect the resistance of Serratia strains against ceftriaxone, but it had no effect on the resistance to other antibiotics. Furthermore, culture supernatant of lactobacilli with concentrations greater than 2%, had an effect on the swarming ability of S. marcescens ATCC 13880 and inhibited it.
Probiotic bacteria and their metabolites have the ability to inhibit virulence factors such as antibiotic resistance and swarming motility and can be used as alternatives to antibiotics.

Acute lymphoblastic leukemia (ALL) is the most common malignancies in the world. Despite advances in treatment of patients with ALL, a subset of patients will have recurrent disease or refractory to chemotherapy and hematopoietic stem cell transplant. Consequently, assessment of the effectiveness of natural compounds with high efficacy and minimal side effects is warranted. In this regard, it has been shown that some of bacterial pigments such as prodigiosin isolated from cell wall of Serratia marcescens have dramatic anti-cancer activities. The aim of this study was to evaluate the effects of prodigiosin on the cell viability and cell number, cell proliferation and apoptosis in CCRF-CEM cell line that serves as a model for ALL cells.
Malignant cells were treated with 100, 200 and 400 nM prodigiosin for 24, 48 and 72 h and cell proliferation-rates were measured by performing WST-1 assay. Furthermore, malignant cells were treated with the indicated concentrations of prodigiosin for 48 h and cell viabilities and cell numbers along with apoptotic-rates were determined by trypan blue staining method and flow cytometer respectively.
Treatment of cells with increasing concentrations of prodigiosin significantly decreased Proliferation-rates in a dose- and time-dependent manner compared to untreated cells. Specifically, after 72 h treatments with 100, 200 and 400 nM prodigiosin, proliferation-rates were measured to be%77.3 ± %1.5, %63 ± %2, and%46.3 ± %3.2 respectively as compared to untreated cells. Furthermore, following 48 h treatments with indicated concentrations of prodigiosin, the cell numbers and viabilities were decreased in a dose-dependent manner. Specifically, treatment with 400 nM prodigiosin resulted in 44% (4.5 × 105 cells) and 63% for cell number and viability respectively as compared to untreated cells. At the same conditions, apoptotic-rates (Early Late) were measured to be 33.8% to 72.8% at the indicated prodigiosin concentrations ranging.
Prodigiosin decreased cell number and viability as well as cell proliferation-rates. This compound also increased apoptosis in CCRF-CEM cells. Therefore, this compound with high pro-apoptotic capacity represents an attractive anti-leukemic agent in ALL.

Chromium (Cr) is an important heavy metal widely used in industries. It is one of the seventeen chemicals with the highest danger to human health according to the United States environmental protection agency (USEPA). The aim of this study was to isolate and identify Cr (VI)-resistant bacteria from Soltan Abad River sediments (Shiraz-Iran) and evaluate their potential for the detoxification of Cr (VI) to Cr (III) under environmental conditions. Bacterial isolates were identified on the basis of colony morphology, Gram staining, and biochemical tests using standard microbiological methods. The minimum inhibitory concentrations (MICs) of chromium were determined by the broth agar dilution method. Cr (VI) reduction assay was determined by measuring the absorbance of the purple complex of Cr (VI) with 1,5-diphenylcarbazide. The growth of Cr (VI)-resistant bacteria was determined at different concentrations of Cr (VI). Finally, the effects of temperature and pH on the growth of selected bacteria and Cr (VI) reduction were investigated using an Luria-Bertani (LB) medium containing 50 mg/L Cr (VI). The results indicated that Pseudomonas aeruginosa and Serratia marcescens were the most resistant bacteria with MICs of 200 and 150 mg/L, respectively. Both bacteria completely reduced 25 and 50 mg/L of Cr (VI) in 36 hours and 48 hours, respectively. The growth rate of both bacteria decreased with increases in the Cr (VI) concentration, and the chromate reduction was directly correlated with the growth of the bacteria. These bacteria were capable of reducing Cr (VI) at a wide range of temperatures (25 to 45°C) and pH levels (5 to 9). The optimum medium conditions for Cr (VI) reduction and the growth of the isolates were temperatures between 30 and 40°C and a pH of 7.0 to 8.0. P. aeruginosa and S. marcescens can be good candidates for the detoxification of Cr (VI) in Soltan Abad River.