Development of a newly designed biosensor using multi-walled carbon nanotubes (MWCNTs) with gold nanoparticles (AuNPs) in the presence of acetaminophen for detection of Escherichia coli.

Escherichia coli is one of the main indicators in the quality control of water, pharmaceuticals, and other samples. Compared with the time-consuming and high prices of the classical methods, with their high risks in the case of insensitive, contamination and offline detections, biosensors have long been a fast and accurate approach for identifying different bacteria. The present study reports the development of a newly electrochemical biosensor using a glassy carbon electrode (GCE) modified by multi-walled carbon nanotubes/AuNPs/E. coli polyclonal antibody/Bovine Serum Albumin in 0.1 M phosphate-buffered saline ( pH 7) in the presence of acetaminophen, for the detection of E. coli in pharmaceuticals and some real samples. Acetaminophen was added as an indicator for the detection of E. coli by changes in conductivity and current. To identify E. coli, square-wave voltammetry (SWV), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) techniques were used. According to the obtained results of square-wave voltammetry, a limit of 3.02 CFU/ml E. coli detection in 3 min with desirable sensitivity, repeatability, and reproducibility was found with the designed biosensor. This biosensor could be a powerful tool for the detection of indicator bacteria in the food industry, drug safety, quality control, clinical diagnostics, and environmental monitoring.

Characterization of oxaliplatin removal by multispecies bacterial populations in moving bed biofilm and suspended-biomass reactors.

AIMS: This work aimed to characterize the oxaliplatin removal potential of multispecies microbial populations using the suspended-biomass (SB) and moving bed biofilm (MBB) reactors. METHODS AND RESULTS: Bacterial strains were isolated from pharmaceutical wastewater, their oxaliplatin degrading potential was screened and oxaliplatin removal efficacy in multispecies bacterial populations was investigated using HPLC. Five bacterial strains able to degrade oxaliplatin with an oxaliplatin removal efficacy of 21%-52% were isolated. The synthetic consortium including Xenorhabdus spp., Pantoea agglomerans and Bacillus licheniformis showed the highest potential with an oxaliplatin removal efficacy of 88.6% and 94.0% using the SB and MBB reactors, respectively. Also, the consortium reduced the chemical oxygen demand (COD) by 91.6 and 33% in MBB and SB reactors, respectively. A kinetic study showed a faster oxaliplatin removal in MBB (0.134 kg-1 ) than in the SB reactor (0.101 kg-1 ). Based on the GS/MS analysis, the overall biochemical pathway of oxaliplatin degradation was hypothesized to be initiated through the oxygenation of diamino-dicyclohexan-platinium complex and the cleavage of the aromatic ring. CONCLUSION: Microbial removal of oxaliplatin using MBB and SB reactors seems to be an efficient and promising approach for oxaliplatin removal in pharmaceutical and hospital wastewater treatment plants. SIGNIFICANCE AND IMPACT OF THE STUDY: Employing bacterial populations using the MBB reactor is a promising way to treat pharmaceutical wastewater to reduce the discharge of anticancer drugs into the environment.

Evaluation of antimicrobial activity of Streptomyces pactum isolated from paddy soils and identification of bioactive volatile compounds by GC-MS analysis.

The objective of this study was to isolate Streptomyces sp. from north paddy soils of Iran and investigation and identification of the bioactive compounds by carrying out GC-MS analysis. Antimicrobial activity was investigated by well diffusion agar technique against the pathogenic microorganisms including Enterococcus faecalis ATCC 29212, Micrococcus luteus ATCC 4698, Bacillus cereus ATCC 11778, Staphylococcus aureus ATCC 9144, Pseudomonas aeruginosa ATCC 27853, Proteus mirabilis ATCC 43071. Based on the results of gene sequencing of gene 16S rRNA and phylogenetic analysis, the isolated sample belongs to the genus Streptomyces with the highest degree of resemblance (99/87%) to the Streptomyces pactum strain ACT12. The isolate showed a broad spectrum of antibacterial activity against test microorganisms. This isolate showed maximum antibacterial activity against M. luteus (25 ± 0.5 mm) and the most resistant microorganism against antibacterial activity of this isolate was P. aeruginosa (9 ± 0.5 mm). The contact bioautography method was used to detect compounds that were responsible for antimicrobial activity and showed the active compounds with Rf values of 0.8-0.9. The identification of bioactive metabolites were performed using gas chromatography-mass spectrometry (GC-MS). GC-MS analysis of the extract showed the presence of 15 volatile compounds. The main compounds were Methyl-3-(3,5-ditertbutyl-4-hydroxyphenyl) (10.88%) and Dibutyl phthalate (8.34%) in comparison with other bioactive compounds. The results showed that north paddy soils of Iran are a rich source of microbial flora for the production of antimicrobial compounds and useful for antimicrobial compounds discovery from Streptomyces sp.

Rapid Detection of Escherichia coli by ß-Galactosidase Biosensor Based on ZnO NPs and MWCNTs: A Comparative Study.

The need for alternative approaches for identifying pathogens has led researchers to focus on nanobiotechnology. In this study, zinc oxide nanoparticles (ZnO NPs) and multi-wall carbon nanotubes (MWCNTs) were used as marker molecules. After measuring the best concentration of these nanomaterials to inhibit the lactase activity of the beta-galactosidase enzymes by binding to them, different concentrations of Escherichia coli were added to the medium and their detection ability was finally compared with each other. Due to small size and high reactivity, these compounds are able to detect very low amount of bacteria in the ambient. In fact, the bacteria are attached to the nanoparticles and detach them from the enzyme and lead to substrate decomposition by the enzyme. MWCNTs exhibited better performance than ZnO NPs in detection of bacteria at very low concentration of 101 CFU/ml in 15 min. As a result, they are very appropriate to be utilized especially in the food industry.

Production of Bioplastic (Polyhydroxybutyrate) with Local Bacillus megaterium Isolated from Petrochemical Wastewater.

BACKGROUND: Polyhydroxybutyrate is a biodegradable plastic produced by some bacteria and can completely be replaced with petroleum based non-degradable plastics. OBJECTIVES: This study was done to isolate and identify one local strain with a high-production ability for industrial purposes. MATERIAL AND METHODS: The sampling from petrochemical wastewater was done. The existence of polyhydroxybutyrate in isolates was studied with Sudan Black staining. Using the Sudan Black B plate assay method and estimating produced PHB amount, the most potent isolate was chosen. This isolate was distinguished by morphological and biochemical methods and determining 16S rRNA gene sequencing. The final confirmation of polyhydroxybutyrate synthesis was done by FTIR and 1H NMR. To increase more production of polyhydroxybutyrate, the effect of different factors including carbon, nitrogen, pH, and temperature were assessed. RESULTS: Six bacterial isolates producing polyhydroxybutyrate were separated, which among them, one new strain of Bacillus megaterium named saba.zh was selected as better isolation. 16S rRNA nucleotide sequence of bacterium was assigned accession number: MN519999 in the NCBI database. The optimal conditions to increase the production of polyhydroxybutyrate, are using glucose as a carbon source, ammonium sulfate as the nitrogen source, in the condition with having pH 7 and temperature 30 °C. After optimizing, the production of PHB increased from 56.51% to 85.41%. CONCLUSIONS: This research indicated that Bacillus megaterium saba.zh, due to better polymer yield, is a potent PHB producer which can be used for PHB industrial production.

Antagonistic Activity of Nocardia brasiliensis PTCC 1422 Against Isolated Enterobacteriaceae from Urinary Tract Infections.

The main drawback of current antibiotic therapies is the emergence and rapid increase in antibiotic resistance. Nocardiae are aerobic, Gram-positive, catalase-positive, non-motile actinomycetes. Nocardia brasiliensis was reported as antibiotic producer. The purpose of the study was to determine antibacterial activity of N. brasiliensis PTCC 1422 against isolated Enterobacteriaceae from urinary tract infections (UTIs). The common bacteria from UTIs were isolated from hospital samples. Antimicrobial susceptibility test was performed for the isolated pathogens using Kirby-Bauer disk diffusion method according to clinical and Laboratory Standards Institute guideline. Antagonistic activity of N. brasiliensis PTCC 1422 was examined with well diffusion methods. Supernatant of N. brasiliensis PTCC 1422 by submerged culture was analyzed with gas chromatography-mass spectrometry. Isolated strains included Escherichia coli, Klebsiella pneumoniae, Serratia marcescens and Proteus mirabilis. The most common pathogen isolated was E. coli (72.5%). Bacterial isolates revealed the presence of high levels of antimicrobial resistances to ceftriaxone and low levels of resistance to cephalexin. Supernatant of N. brasiliensis PTCC 1422 showed antibacterial activity against all of the isolated microorganisms in well diffusion method. The antibiotic resistance among the uropathogens is an evolving process, so a routine surveillance to monitor the etiologic agents of UTI and the resistance pattern should be carried out timely to choose the most effective empirical treatment by the physicians. Our present investigation indicates that the substances present in the N. brasiliensis PTCC 1422 could be used to inhibit the growth of human pathogen. Antibacterial resistance among bacterial uropathogen is an evolving process. Therefore, in the field on the need of re-evaluation of empirical treatment of UTIs, our present. The study has demonstrated that N. brasiliensis PTCC 1422 has a high potential for the treatment of UTIs.

Occurrence of deoxynivalenol (DON) in wheat flours in Guilan province, northern Iran.

INTRODUCTION AND OBJECTIVE: Deoxynivalenol (DON) is one of several mycotoxins produced by certain Fusarium species that frequently infect wheat, corn, rice, oats, barley and other grains in the field or during storage. Guilan, Golestan and Mazandaran areas are located in the North Iran with favorite conditions for Fusarium growth. DON affects animal and human health causing vomiting, acute temporary nausea, diarrhea, abdominal pain, headache, dizziness, and fever. MATERIALS AND METHODS: In this study, a total of 96 wheat flour samples of different types were collected during summer 2013 from six flour mills in Northern Iran. All samples were analyzed for DON by enzyme-linked immunosorbent assay. RESULTS: DON was detected in 80 out of 96 wheat flour samples (83.33%), at levels ranging from 23 to 1270 µg/kg. The maximum contamination level of DON (1270 µg/kg) was found in whole flour while the minimum value (23 µg/kg) was registered in debranned flour. The mean of contamination was 630.53 µg/kg. CONCLUSIONS: According to results obtained, incidence and contamination levels of DON, seem to be a serious problem for public health. Therefore, cereal and cereal based foods should be controlled for the presence of toxins, storage conditions and moisture content, which is considered a major factor in the growth of the Fusarium fungi.

Isolation and identification of Vibrio parahaemolyticus from seawater and sediment samples in the southern coast of the Caspian Sea.

The objectives of this study were to investigate the occurrence of Vibrio parahaemolyticus in the seawater and its sediment by molecular techniques and conventional microbiological methods. Of 300 samples analyzed, 20.3 % was recorded positive for V. parahaemolyticus. Of the 62 strains isolated, 26 (8.3 %) were obtained from the seawater samples, and 36 (12 %); from sediments. Only three strains (4.83 %) showed hemolytic activity in Wagatsuma agar. The results of this study demonstrated the presence of V. parahaemolyticus in the southern coast of the Caspian Sea (Northern Iran). Furthermore, the PCR approach proved useful for reliable confirmation of species identification. V. parahaemolyticus is an important human pathogen responsible for food-borne gastroenteritis worldwide. These findings indicated the potential sanitary risk associated with the presence of pathogenic V. parahaemolyticus in the Caspian Sea.

λ Phage nanobioparticle expressing apoptin efficiently suppress human breast carcinoma tumor growth in vivo.

Using phages is a novel field of cancer therapy and phage nanobioparticles (NBPs) such as λ phage could be modified to deliver and express genetic cassettes into eukaryotic cells safely in contrast with animal viruses. Apoptin, a protein from chicken anemia virus (CAV) has the ability to specifically induce apoptosis only in carcinoma cells. We presented a safe method of breast tumor therapy via the apoptin expressing λ NBPs. Here, we constructed a λ ZAP-CMV-apoptin recombinant NBP and investigated the effectiveness of its apoptotic activity on BT-474, MDA-MB-361, SKBR-3, UACC-812 and ZR-75 cell lines that over-expressing her-2 marker. Apoptosis was evaluated via annexin-V fluorescent iso-thiocyanate/propidium iodide staining, flow-cytometric method and TUNEL assay. Transfection with NBPs carrying λ ZAP-CMV-apoptin significantly inhibited growth of all the breast carcinoma cell lines in vitro. Also nude mice model implanted BT-474 human breast tumor was successfully responded to the systemic and local injection of untargeted recombinant λ NBPs. The results presented here reveal important features of recombinant λ nanobioparticles to serve as safe delivery and expression platform for human cancer therapy.