Detoxification of aflatoxin B1 by certain bacterial species isolated from Egyptian soil

2011 ◽  
Vol 4 (2) ◽  
pp. 169-176 ◽  
Author(s):  
M. Elaasser ◽  
R. El Kassas
Keyword(s):  
Culture Supernatant ◽  
Bacterial Species ◽  
Industrial Applications ◽  
Aflatoxin Contamination ◽  
Soil Samples ◽  
Proteinase K ◽  
Strong Inhibitor ◽  
E Coli ◽  
Screening Experiments ◽  
Cell Extracts

Aflatoxin contamination of food and grain poses a serious economic and health problem worldwide. Aflatoxin B1 (AFB1) is extremely mutagenic, toxic and a potent carcinogen to both humans and livestock. A safe, effective and environmentally sound detoxification method is needed for controlling this toxin. In this study, 21 soil samples were screened from various sources with vast microbial populations using a coumarin containing medium. Eleven bacterial isolates showing AFB1 reduction activity in a liquid culture medium were selected from the screening experiments. Isolate 12-3 and 12-5, obtained from soil samples of Kafr-Zaiat Pesticide company drainage and identified to be Pseudomonas putida and Escherichia coli, reduced AFB1 by 69.3% and 58.8%, respectively, after incubation in the liquid medium at 37 °C for 72 h. The culture supernatant of these isolates was able to reduce AFB1 effectively by 76.2% and 62.5%, respectively, whereas the viable cells and cell extracts were far less effective. Factors influencing AFB1 detoxification by the culture supernatant were investigated. The highest detoxification activity for P. putida and E. coli was 83.3% and 63.8%, respectively, at pH 8 and 30 °C for 72 h. The detoxification activity was reduced at 10, 20 and 45 °C. The Mg2+, Mn2+, Se and Cu2+ ions were activators for AFB1 detoxification. However, Zn2+ ion was a strong inhibitor. Treatments with proteinase K, proteinase K plus SDS and heating significantly reduced or eradicated the detoxification activity of the culture supernatant. In conclusion, the detoxification of AFB1 by P. putida 12-3 was enzymatic and the enzymes responsible for the detoxification of AFB1 are constitutively extracellular produced. Also, the AFB1 detoxification by E. coli was conducted by enzymes as well as by cell wall binding mechanism. Both bacteria could have great potential in industrial applications.

Degradation of zearalenone in swine feed and feed ingredients by Bacillus subtilis ANSB01G

2014 ◽  
Vol 7 (2) ◽  
pp. 143-151 ◽  
Author(s):  
Y.P. Lei ◽  
L.H. Zhao ◽  
Q.G. Ma ◽  
J.Y. Zhang ◽  
T. Zhou ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Culture Supernatant ◽  
Antimicrobial Activities ◽  
Proteinase K ◽  
Rrna Gene ◽  
Distillers Grains With Solubles ◽  
Dried Distillers Grains ◽  
Cell Extracts ◽  
Gene Sequence Analysis ◽  
And Staphylococcus Aureus

Zearalenone (ZEA) and its derivatives are mycotoxins that can cause oestrogenic effects and impair the reproductive physiology of animals, especially in female swine. Strategies to reduce or eliminate ZEA contamination in foods and feeds are very much needed. Among 36 bacterial isolates obtained from a variety of animal intestinal chyme, mouldy foods and feeds, soils, etc., five isolates demonstrated the ability to reduce more than 50% of ZEA in a liquid medium; ANSB01G isolate taken from normal broiler intestinal chyme reduced ZEA the most, by 88.65%. Using physiological, biochemical, and 16S rRNA gene sequence analysis methods, the ANSB01G isolate was identified as Bacillus subtilis. Under simulated intestinal tract conditions, the ANSB01G B. subtilis isolate degraded 84.58, 66.34 and 83.04% of ZEA in naturally contaminated maize, dried distillers’ grains with solubles, and swine complete feed, respectively. The highest degradation of ZEA occurred when the mycotoxin was co-incubated with the whole bacterial culture, resulting in a reduction of 88.65%, followed by 75.60% using culture supernatant, 26.11% using cell extracts, and 15.06% using viable cells. Treatments consisting of both heating and addition of proteinase K significantly reduced the rate of ZEA degradation in the culture supernatant, indicating that the ZEA degradation might be enzymatic. B. subtilis ANSB01G displayed resistance to simulated gastrointestinal tract environments and antimicrobial activities against several common bacterial pathogens, including Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. These properties of B. subtilis ANSB01G suggest the possibility of its potential to effectively degrade ZEA in feed and to develop functional feed products for livestock industries.

scholarly journals A putative microcin amplifies Shiga toxin 2a production ofEscherichia coliO157:H7

2019 ◽  
Author(s):  
Hillary M. Figler ◽  
Lingzi Xiaoli ◽  
Kakolie Banerjee ◽  
Maria Hoffmann ◽  
Kuan Yao ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Bacterial Infections ◽  
Bacterial Species ◽  
Treatment Options ◽  
Gene Clusters ◽  
Toxin Production ◽  
Additional Treatment ◽  
Proteinase K ◽  
Gut Microflora ◽  
E Coli

AbstractEscherichia coliO157:H7 is a foodborne pathogen, implicated in various multi-state outbreaks. It encodes Shiga toxin on a prophage, and Shiga toxin production is linked to phage induction. AnE. colistrain, designated 0.1229, was identified that amplified Stx2a production when co-cultured withE. coliO157:H7 strain PA2. Growth of PA2 in 0.1229 cell-free supernatants had a similar effect, even when supernatants were heated to 100°C for 10 min, but not after treatment with Proteinase K. The secreted molecule was shown to use TolC for export and the TonB system for import. The genes sufficient for production of this molecule were localized to a 5.2 kb region of a 12.8 kb plasmid. This region was annotated, identifying hypothetical proteins, a predicted ABC transporter, and a cupin superfamily protein. These genes were identified and shown to be functional in two otherE. colistrains, and bioinformatic analyses identified related gene clusters in similar and distinct bacterial species. These data collectively suggestE. coli0.1229 and otherE. coliproduce a microcin that induces the SOS response in target bacteria. Besides adding to the limited number of microcins known to be produced byE. coli, this study provides an additional mechanism by whichstx2aexpression is increased in response to the gut microflora.ImportanceHow the gut microflora influences the progression of bacterial infections is only beginning to be understood. Antibiotics are counter-indicated forE. coliO157:H7 infections, and therefore treatment options are limited. An increased understanding of how the gut microflora directs O157:H7 virulence gene expression may lead to additional treatment options. This work identifiedE. colithat enhance the production of Shiga toxin by O157:H7, through the secretion of a proposed microcin. This work demonstrates another mechanism by which non-O157E. colistrains may increase Shiga toxin production, and adds to our understanding of microcins, a group of antimicrobials that are less well understood than colicins.

scholarly journals The Rhizobium etli cyaC Product: Characterization of a Novel Adenylate Cyclase Class

2002 ◽  
Vol 184 (13) ◽  
pp. 3560-3568 ◽  
Author(s):  
Juan Téllez-Sosa ◽  
Nora Soberón ◽  
Alicia Vega-Segura ◽  
María E. Torres-Márquez ◽  
Miguel A. Cevallos
Keyword(s):  
Xanthomonas Campestris ◽  
Sinorhizobium Meliloti ◽  
Bacterial Species ◽  
Activity Levels ◽  
Rhizobium Etli ◽  
Mesorhizobium Loti ◽  
E Coli ◽  
Cell Extracts ◽  
Product Characterization ◽  
Organic Hydroperoxides

ABSTRACT Adenylate cyclases (ACs) catalyze the formation of 3′,5′-cyclic AMP (cAMP) from ATP. A novel AC-encoding gene, cyaC, was isolated from Rhizobium etli by phenotypic complementation of an Escherichia coli cya mutant. The functionality of the cyaC gene was corroborated by its ability to restore cAMP accumulation in an E. coli cya mutant. Further, overexpression of a malE::cyaC fusion protein allowed the detection of significant AC activity levels in cell extracts of an E. coli cya mutant. CyaC is unrelated to any known AC or to any other protein exhibiting a currently known function. Thus, CyaC represents the first member of a novel class of ACs (class VI). Hypothetical genes of unknown function similar to cyaC have been identified in the genomes of the related bacterial species Mesorhizobium loti, Sinorhizobium meliloti, and Agrobacterium tumefaciens. The cyaC gene is cotranscribed with a gene similar to ohr of Xanthomonas campestris and is expressed only in the presence of organic hydroperoxides. The physiological performance of an R. etli cyaC mutant was indistinguishable from that of the wild-type parent strain both under free-living conditions and during symbiosis.

scholarly journals Biomineralization of Platinum by Escherichia coli

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 407 ◽  
Author(s):  
Sahar Shar ◽  
Frank Reith ◽  
Esmaeil Shahsavari ◽  
Eric Adetutu ◽  
Yuana Nurulita ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Liquid Culture ◽  
Bacterial Species ◽  
Platinum Complexes ◽  
Industrial Applications ◽  
Bacterial Survival ◽  
Platinum Concentration ◽  
E Coli ◽  
The Impact ◽  
Scanning Electron

The widespread use of platinum in many industrial applications has led to its release into the environment at elevated concentrations with potential adverse effects on human and environmental health. However, the nature of interactions between mobile platinum complexes and the biotic components of the environment, which are increasingly being exposed to platinum, is poorly studied. The aim of this study was to assess the impact of Pt(IV)-chloride on the growth and activity of the well-characterized bacteria Escherichia coli. Bacterial survival and viability in the presence of different concentrations of Pt(IV)-chloride were assessed in liquid culture, while platinum retention was assessed using experimentation with sand-filled columns with the residual platinum concentration measured by atomic absorption spectroscopy. Bacterial biomineralization of platinum was studied with scanning electron microscopy. The results showed that E. coli tolerated PtCl4 at concentrations of up to 10,000 µM over 21 days and remained viable after 112 days of incubation with PtCl4 at 10,000 µM in sand columns. Overall, 74 wt.% and 50 wt.% of platinum was mineralized in E. coli and blank sand columns, respectively. The results of this study confirm that E. coli is capable of biomineralizing platinum. The results confirm that the interaction of platinum with bacteria is not limited to known metal-resistant bacterial species.

scholarly journals Antagonistic Potential of Dairy Origin Enterococcus faecium Against Multidrug-Resistant Foodborne Pathogens

2021 ◽  
Vol 26 (2) ◽  
pp. 2406-2415
Author(s):  
SANA WAHEED ◽  
◽  
MUHAMMAD HIDAYAT RASOOL ◽  
BILAL ASLAM ◽  
SAIMA MUZAMMIL ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Foodborne Pathogens ◽  
Culture Supernatant ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Proteinase K ◽  
E Coli ◽  
Probiotic Potential ◽  
Proteinase K Treatment ◽  
Cell Free Culture Supernatant

Probiotic potential of Enterococcus spp. is widely investigated around the globe. The biochemically and molecular characterized E. faecium strains isolated from Dahi (continental yogurt) were evaluated to tolerate simulated gastric environment, bile, sodium chloride, temperature, and pH. The safety was assessed by disc diffusion, broth microdilution, antibiotic resistance genes screening, and hemolytic ability. Enterococci survived simulated gastrointestinal conditions and depicted growth at temperature (15 to ≥42°C), pH (≤2.5 to ≥9.5), 0.3% bile salt and 3% NaCl. All strains were sensitive to ampicillin, vancomycin, kanamycin, gentamicin, streptomycin, tetracycline and ciprofloxacin and harbored vanR, vanX, qnrB2, qnrS, tetK, and tetW resistance genes. E. faecium strains inhibited the E. coli (85%) and S. Typhi (50%) whereas the 10% cell-free culture supernatant (CFCS) of E. faecium halted the growth of E. coli while 15% CFCS completely suppressed S. Typhi. The cell-free culture supernatant retained antibacterial nature after pH and proteinase K treatment, however, it lost activity after heat treatment (≥95°C). The genetic screening revealed that all isolates are capable to produce putrescine biogenic amine. Further assessment of strains for lack of infectivity, cytotoxicity in animals, adhesion to Caco-2 cells and characterization of enterocins is essential to conclude the probiotic potential of these strains.

Usefulness of a Multiplex PCR for Detection of Diarrheagenic Escherichia coli in a Diagnostic Microbiology Laboratory Setting

2016 ◽  
Vol 1 (2) ◽  
pp. 38-42 ◽  
Author(s):  
Khairun Nessa ◽  
Dilruba Ahmed ◽  
Johirul Islam ◽  
FM Lutful Kabir ◽  
M Anowar Hossain
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Clinical Laboratory ◽  
Proteinase K ◽  
Microbiology Laboratory ◽  
Pcr Assay ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Multiplex Pcr Assay ◽  
Diagnostic Microbiology

A multiplex PCR assay was evaluated for diagnosis of diarrheagenic Escherichia coli in stool samples of patients with diarrhoea submitted to a diagnostic microbiology laboratory. Two procedures of DNA template preparationproteinase K buffer method and the boiling method were evaluated to examine isolates of E. coli from 150 selected diarrhoeal cases. By proteinase K buffer method, 119 strains (79.3%) of E. coli were characterized to various categories by their genes that included 55.5% enteroaggregative E. coli (EAEC), 18.5% enterotoxigenic E. coli (ETEC), 1.7% enteropathogenic E. coli (EPEC), and 0.8% Shiga toxin-producing E. coli (STEC). Although boiling method was less time consuming (<24 hrs) and less costly (<8.0 US $/ per test) but was less efficient in typing E. coli compared to proteinase K method (41.3% vs. 79.3% ; p<0.001). The sensitivity and specificity of boiling method compared to proteinase K method was 48.7% and 87.1% while the positive and negative predictive value was 93.5% and 30.7%, respectively. The majority of pathogenic E. coli were detected in children (78.0%) under five years age with 53.3% under one year, and 68.7% of the children were male. Children under 5 years age were frequently infected with EAEC (71.6%) compared to ETEC (24.3%), EPEC (2.7%) and STEC (1.4%). The multiplex PCR assay could be effectively used as a rapid diagnostic tool for characterization of diarrheagenic E. coli using a single reaction tube in the clinical laboratory setting.Bangladesh J Med Microbiol 2007; 01 (02): 38-42

Sidrophore Production and Phosphate Solubilization by Bacillus cereus and Pseudomonas fluorescens Isolated from Iraqi Soils and Soil Characterization

2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Zaid Raad Abbas ◽  
Aqeel Mohammed Majeed Al-Ezee ◽  
Sawsan H
Keyword(s):  
Bacillus Cereus ◽  
Pseudomonas Fluorescens ◽  
Phosphate Solubilization ◽  
Bacterial Species ◽  
Nutrient Status ◽  
Bacterial Count ◽  
Soil Samples ◽  
Phosphate Solubilizing Bacteria ◽  
Clear Zone ◽  
Zone Formation

This study was conducted to explore the ability of Pseudomonas fluorescens and Bacillus cereus to solubilizing a phosphate in soil for enhancing the planting growth and, its relation with soill characterization. The isolates were identified as P.fluorescens and B. cereus using convential analysis and, its phosphate solubilization ability and sidrophore was shown by the clear zone formation on National Botanical Research Institute���s Phosphate medium. Moreover, Pseudomonas fluorescens isolates (n = 9) and three of B. cereus isolated from agricultural area in Baghdad university, Mustansiriyah university and Diyala bridge. Results displayed that bacterial count were varied in soil samples according to their region, and ranging from 30 to 60 *10 2 CFU/g in Baghdad university soil to 10���20 *10 2 CFU/g in Mustansiriyah university soil, the Baghdad soil macronutrient which included: NH4, NO3, P, and K were, 8.42, 20.53, 19.09, 218.73 respectively, While the physio analysis revealed that the mean of pH was 7.3 and EC was 8.63. on the other hand the micronutrient analysis indicated that the soil samples were included Ca, Fe, Mn, Zn and Cu which gave their mean 5025.9, 8.9, 4.9, 0.5 and 1.5 respectevily. Results revealed that all isolated bacteria (9 isolates of P.fluorescens and three isolates of B. cereus gave ahalo zone which mean their ability to be phosphate solubilizing bacteria at 100%. Results revealed that all isolated bacteria were detected a ability to produce high levels from chelating agents (siderophores)) by P.fluorescens and. B cereus at 100%, when appeared ahalo clear zone. Furthermore, the high levels of phosphate solubilization and siderophore production were grouped in bacterial species isolated from Iraqi soils. might be attributed to many soil factors such as soil nutrient status, soil acidity, water content, organic matter and soil enzyme activities.

Efficacy of Silver Nanoparticles Synthesized from Hymenocallis species (Spider Lilly) Leaf Extract as Antimicrobial Agents

2019 ◽  
Vol 12 (5) ◽  
pp. 4644-4647
Author(s):  
K.K. Gupta ◽  
Neha Kumari ◽  
Neha Sinha ◽  
Akruti Gupta
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Antimicrobial Agents ◽  
Color Change ◽  
Bacterial Species ◽  
Antimicrobial Property ◽  
Biogenic Synthesis ◽  
E Coli ◽  
Light Yellow ◽  
Antibiotic Property

Biogenic synthesis of silver nanoparticles synthesized from Hymenocallis species (Spider Lilly) leaf extract was subjected for investigation of its antimicrobial property against four bacterial species (E. coli, Salmonella sp., Streptococcus sp. & Staphylococcus sp.). The results revealed that synthesized nanoparticles solution very much justify the color change property from initial light yellow to final reddish brown during the synthesis producing a characteristics absorption peak in the range of 434-466 nm. As antimicrobial agents, their efficacy was evaluated by analysis of variance in between the species and among the different concentration of AgNPs solution, which clearly showed that there was significant variation in the antibiotic property between the four different concentrations of AgNPs solution and also among four different species of bacteria taken under studies. However, silver nanoparticles solution of 1: 9 and 1:4 were proved comparatively more efficient as antimicrobial agents against four species of bacteria.

Transport of escherichia coli through soil to groundwater traced by randomly amplified polymorphic DNA (RAPD)

1997 ◽  
Vol 35 (11-12) ◽  
pp. 351-357 ◽  
Author(s):  
R. Rothmaier ◽  
A. Weidenmann ◽  
K. Botzenhart
Keyword(s):  
Negative Impact ◽  
Random Amplified Polymorphic Dna ◽  
Coli Strain ◽  
Soil Samples ◽  
Test Field ◽  
Liquid Manure ◽  
E Coli ◽  
Rapd Pattern ◽  
Geological Situation ◽  
Different Strains

Isolates (50) of E. coli obtained from liquid manure (20 bovine, 20 porcine) were genotyped using random amplified polymorphic DNA (RAPD). Typing revealed 9 and 14 different strains in bovine and porcine liquid manure respectively with no strains in common. One porcine strain, showing a simple RAPD pattern, was subcultured and spread on a test field (1.5l/m2 at 1010 cfu/l) in a drinking water protection zone with loamy to sandy sediments in the Donauried area, Baden-Wurttemberg. Soil samples and groundwaters were collected at monthly intervals October 1994 – June 1995 during which 114 E. coli isolates were recovered. The first occurrence and maximum concentration of E. coli in soil samples taken from more than 20cm depth was in January 1995, declining rapidly with depth and time. All isolates from soil and only one from groundwater showed the RAPD pattern of the spread E. coli strain. The results could not demonstrate a severe negative impact of the spreading of liquid manure on the bacteriological quality of the groundwater in the given geological situation. The distinct strain patterns found in different kinds of liquid manure suggest that genotyping of E. coli by RAPD may be an adequate tool for tracing sources of faecal contamination.

Substituted 6,7-dimethoxy-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole- 3-1,1-dioxide Derivatives with Antimicrobial Activity and Docking Assisted Prediction of the Mechanism of their Antibacterial and Antifungal Properties

2020 ◽  
Vol 20 (29) ◽  
pp. 2681-2691
Author(s):  
Athina Geronikaki ◽  
Victor Kartsev ◽  
Phaedra Eleftheriou ◽  
Anthi Petrou ◽  
Jasmina Glamočlija ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antifungal Activity ◽  
Drug Targets ◽  
Bacterial Species ◽  
Pharmaceutical Research ◽  
Docking Studies ◽  
Fungal Species ◽  
Docking Analysis ◽  
E Coli ◽  
Antibacterial And Antifungal

Background: Although a great number of the targets of antimicrobial therapy have been achieved, it remains among the first fields of pharmaceutical research, mainly because of the development of resistant strains. Docking analysis may be an important tool in the research for the development of more effective agents against specific drug targets or multi-target agents 1-3. Methods: In the present study, based on docking analysis, ten tetrahydrothiazolo[2,3-a]isoindole derivatives were chosen for the evaluation of the antimicrobial activity. Results: All compounds showed antibacterial activity against eight Gram-positive and Gram-negative bacterial species being, in some cases, more potent than ampicillin and streptomycin against all species. The most sensitive bacteria appeared to be S. aureus and En. Cloacae, while M. flavus, E. coli and P. aeruginosa were the most resistant ones. The compounds were also tested for their antifungal activity against eight fungal species. All compounds exhibited good antifungal activity better than reference drugs bifonazole (1.4 – 41 folds) and ketoconazole (1.1 – 406 folds) against all fungal species. In order to elucidate the mechanism of action, docking studies on different antimicrobial targets were performed. Conclusion: According to docking analysis, the antifungal activity can be explained by the inhibition of the CYP51 enzyme for most compounds with a better correlation of the results obtained for the P.v.c. strain (linear regression between estimated binding Energy and log(1/MIC) with R 2 =0.867 and p=0.000091 or R 2 = 0.924, p= 0.000036, when compound 3 is excluded.

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