Physiological factors affecting the production of an antimicrobial substance by Streptomyces violatus in batch cultures

Egyptian Journal of Biology Vol.3 2001: 1-1

Complete genome sequence of Lactobacillus plantarum 10CH, a potential probiotic lactic acid bacterium with potent antimicrobial aActivity

Lactobacillus plantarum 10CH is a bacteriocin-producing potential probiotic lactic acid bacterium (LAB) strain isolated from cheese. Its complete nucleotide sequence shows a single circular chromosome of 3.3 Mb, with a G+C content of 44.51%, a 25-gene plantaricin bacteriocin gene cluster, and the absence of recognized virulence factors. [Abstract copyright: Copyright © 2017 El Halfawy et al.

Searching for molecular markers in head and neck squamous cell carcinomas (HNSCC) by statistical and bioinformatic analysis of larynx-derived SAGE libraries

Background: Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignancies in humans. The average 5-year survival rate is one of the lowest among aggressive cancers, showing no significant improvement in recent years. When detected early, HNSCC has a good prognosis, but most patients present metastatic disease at the time of diagnosis, which significantly reduces survival rate. Despite extensive research, no molecular markers are currently available for diagnostic or prognostic purposes. Methods: Aiming to identify differentially-expressed genes involved in laryngeal squamous cell carcinoma (LSCC) development and progression, we generated individual Serial Analysis of Gene Expression (SAGE) libraries from a metastatic and non-metastatic larynx carcinoma, as well as from a normal larynx mucosa sample. Approximately 54,000 unique tags were sequenced in three libraries. Results: Statistical data analysis identified a subset of 1,216 differentially expressed tags between tumor and normal libraries, and 894 differentially expressed tags between metastatic and non-metastatic carcinomas. Three genes displaying differential regulation, one down-regulated (KRT31) and two up-regulated (BST2, MFAP2), as well as one with a non-significant differential expression pattern (GNA15) in our SAGE data were selected for real-time polymerase chain reaction (PCR) in a set of HNSCC samples. Consistent with our statistical analysis, quantitative PCR confirmed the upregulation of BST2 and MFAP2 and the downregulation of KRT31 when samples of HNSCC were compared to tumor-free surgical margins. As expected, GNA15 presented a non-significant differential expression pattern when tumor samples were compared to normal tissues. Conclusion: To the best of our knowledge, this is the first study reporting SAGE data in head and neck squamous cell tumors. Statistical analysis was effective in identifying differentially expressed genes reportedly involved in cancer development. The differential expression of a subset of genes was confirmed in additional larynx carcinoma samples and in carcinomas from a distinct head and neck subsite. This result suggests the existence of potential common biomarkers for prognosis and targeted-therapy development in this heterogeneous type of tumor.Fundação de Amparo a Pesquisa do Estado de São Paulo/FAPESP [05/51467-0]; [04/12054-9]; [07/50894-7]Ludwig Institute for Cancer ResearchConselho Nacional de Pesquisas/CNPqCoordenacao de Aperfeicoamento do Pessoal do Ensino Superior/CAPE

Induction of sporulation and antibacterial activity in the aerial mycelium negative mutants of Streptomyces nasri

Egyptian Journal of Biology Vol.3 2001: 23-3

The Application of Mediated Biosynthesized Green Silver Nanoparticles by Streptomyces griseorubens in Water Treatment

In the present study, a soil actinomycete was isolated from near the river Nile shoreline, Egypt. The identification of this isolate as Streptomyces griseorubens was performed using 16s rDNA. The sequence has been deposited in the Gene Bank with the accession number LC066679. Factors affecting the biogenesis of AgNPs were optimized by applying the Plackett-Burman factorial design. The maximum silver nanoparticles (AgNPs) biosynthesis (2.76 OD at 400 nm) was achieved in the trial No.9 that contained the following ingredients (g/L): Starch (20); MgSO4 (0.05); K‚ HPO4 (1.0); NaNO3 (2.0); AgNO3 (1.0) mmol/l; PH (7); incubated at temperature 30°C for 72 hr. The biosynthesized nanoparticles were characterized using spectroscopic techniques. AgNPs showed the characteristic UV spectra at a wavelength range 300 - 600 nm and a characteristic absorption peak was recorded at the wavelength of 400 nm. For AgNPs with absorbance height ofH≈2.56 a.u. and peak width at half maximum absorbance (PWHM) H≈120 nm which remained constant over a long period of time indicating its stability. FTIR spectra showed the functional group of the biomaterials capping the AgNPs. EDX confirmed the formation of the metallic silver nanoparticles, indicating the presence of proteinaceous cabbing. TEM micrograph showed spherical AgNPs in shape with an average diameter of 22 nm. The biosynthesized AgNPs showed high stability up-to two weeks. The conjugate (AgNPs/cellulosic fiber (C)) of Luffa aeygptiaca and (AgNPs/activated carbon (AC)) was applied for drinking water treatment, which resulted in fecal Coliform bacteria removal with a success of 99.9% as a water treatment application

Isolation and characterisation of an antimicrobial substance produced by Streptomyces violatus

Egyptian Journal of Biology Vol.3 2001: 11-2

Characterization of Carotenogenic Rhodotorula Strains Isolated from Delta Region, Egypt and their Potential for Carotenoids Production

Initial visual screening for most applicable strains visually based on cell-bound pigmented colonies from different sources in the Egyptian environment. Samples (n=25) of soil, milk, laban rayeb, and kareesh and Ras cheeses were screened for strains capable of producing carotenoids. Seven isolates showed fast growth rates and high content of carotenoids were further characterized. Physiological and molecular identification of the isolated yeast was done using API 32C and sequencing of 18S rRNA gene. The produced sequences were compared with reference 18S rRNA gene sequences available in NCBI GenBank database. Five yeasts strains (S-361, S-37, S-33, S-11 and S-10) out of seven were identified as R. diobovata [with accession no. KX866280, KX866279, KX866278, KX866276 and KX866275 respectively] and the rest were classified as R. mucilaginosa (S-5 and M-30) with accession no: KX866274 and KX866277. The carotenoid derivatives produced by R. diobovata S-361 and R. mucilaginosa S-5 strains were identified by chromatographic analysis (TLC and HPLC) to be b-carotene as a major fraction, torulene, torulene-like and torulahodine. The ability of R. diobovata S-361 strain to produce carotenoids from lactose hydrolyzed salt whey in bioreactor and high aeration led to promote growth resulted in high biomass production (22.7 g/l at day five). Also the production of yeast biomass was about 3.5 times higher yield than in Erlenmeyer flasks while high cellular carotenoids production obtained at day four (147 µg/g) and torulene was the most dominant carotenoids fraction, Cellular and volumetric carotenoids production in batch fermentation during 5 days was investigated. The highest cellular carotenoids were recorded in pellets of the culture of R. diobovata S-361

Statistical Bioprocess Strategies for Bio-Fabrication of Nano-Ag from Streptomyces rectiviolaceus Strain SMWN3.2 as a Novel Antimicrobial Agent against Hospital-Acquired Infectious Pathogens

The application of actinomycetes for bio-fabrication of silver nanoparticles as a rapid, eco-friendly and promising approach is desired for its non-toxicity and simplicity advantages. From sixteen actinomycetes were isolated and checked for their ability to produce nano-Ag, Streptomyces rectiviolaceus strain SMWN3.2 showed more effective nano-Ag (surface plasmon resonance peak at 420 nm and its size 10nm) as an antimicrobial agent. Comparing with the biological process microbial nano –Ag synthesis have advantageous because of its natural abundance, easy culture and its potential to scale up for large scale synthesis, By using Plackett-Burman and Box-Behnken experimental designs the optimized medium components recorded the larger biomass production (16g/l) than the basal conditions (3.8 folds). Also, the optimal nano-Ag bio-fabrication conditions were 0.5M silver nitrate and 5v/v cell filtrate at 45°C. Kinetic conversion rates in submerged batch cultivation in 7L stirred bioreactor was: YX =30.5, Pmax =85.5g/l and YP = 42.6 at 30hr. The best nano-Ag concentrations that formed large inhibition zones were 35- 60µg/ml and the MIC/ MBC and MIC/MFC measured as 25µg/ml/50µg/ml, 50µg/ml/60µg/ml which showed against Streptococcus pneumoniae and Aspergillus fumigatus respectively. This work is focuses on large-scale production of nano-Ag as an antimicrobial agent against hospital-acquired infectious pathogens

Endotoxin Production by Pseudomonas aeruginosa ATCC 9027 with Potential Medical Applications

Four Gram-negative bacteria (E.coli ATCC 19404, P. aeruginosa ATCC9027, A. hydrophila ATCC 7966 and V. damsel ATCC 33539) were screened for production of endotoxin. P. aeruginosa recoded the highest endotoxin concentration (338.59 x 103 IU/ml). The optimization of endotoxin production resulted in the increase of endotoxin titer (25% at pH 7.0 and 26% at both 30°C and 90 rpm). The detection of lipid core complex (50 kDa) and O-specific polysccahrides (20, 25, 38 kDa) was performed by the application of SDS-PAGE. GC/MS analysis indicated the presence of 4 compounds namely 2H Pyaran, 2,5 diethenyltetrahydro, Tetradecanoic acid, Bis(2 ethylhexyl) phthalate and Dodecanoic acid. The endotoxin was thermally stable (78%) at 120°C for 60 min. Reduction of endotoxin activity (45 and 69%) occurred when treated with 1N-NaOH or HCl for 60 min, respectively. The endotoxin showed a bio-toxicity against Artemia salina, (LC50of 102.99µg/ml). The endotoxin exhibited antitumor activity against colon cancer cells (Caco-2) and breast cancer cells (Mcf-7) with growth reduction amounted to87% and 92%, respectively. On the other hand, a weak antiviral activity (5.2%) was recorded in Vero cells infected with HAV. In conclusion, the endotoxin with antioxidant property could be an alternative for the treatment of colon and breast cancer