Ahmet Adiguzel

Antimicrobial activity of aqueous and methanol extracts of Juniperus oxycedrus L.

Aqueous and methanol extracts of the leaves of Juniperus oxycedrus were investigated for their in vitro antimicrobial properties. The plant was collected from Pelitli Village of Gebze, Kocaeli, in the Marmara region of Turkey. Juniperus oxycedrus is widely used as traditional folk medicine in Turkey for treatment of different infectious diseases. The antimicrobial activity of the extracts against 143 laboratory strains belonging to 56 bacterial species, and 31 isolates of 5 fungi species were evaluated based on the inhibition zone using the disc-diffusion assay, minimal inhibition concentration (MIC) and minimal bactericidal concentration (MBC) values. The aqueous extract of J. oxycedrus had no antimicrobial effect against the test microorganisms whereas the methanol extract had inhibitory effects on the growth of 57 strains of 24 bacterial species in the genera of Acinetobacter, Bacillus, Brevundimonas, Brucella, Enterobacter, Escherichia, Micrococcus, Pseudomonas, Staphylococcus, and Xanthomonas. In addition 11 Candida albicans isolates at a concentration of 31.25-250 micro g/ml were also inhibited.

Evaluation of antimicrobial activities of Satureja hortensis L.

The present study was designated to evaluate the antimicrobial activities of methonol and hexane extracts of Satureja hortensis L. which is an annual herb used as traditional folk medicine in Eastern Anatolia region of Turkey for the treatment of different infectious diseases and disorders. The antimicrobial activities of the extracts against 147 laboratory strains belong to 55 bacterial species, and 31 isolates of 1 yeast and 4 fungi species were tested by using disc diffusion assay. The results showed that hexane extract of Satureja hortensis had no antifungal, but antibacterial activity against four strains of three Bacillus species whereas methanol extract of Satureja hortensis had both anticandidal and antibacterial effects. It inhibited the growth of 23 strains of 11 bacterial species and 6 isolates of Candida albicans, at the concentration of 300microg/ml. Satureja hortensis did not show antimicrobial activity against the remaining microorganisms (83%) tested including most and all of the clinic and plant pathogenic microorganisms, respectively. Methanol extract showed stronger and broader spectrum of antimicrobial activity as compared to hexane extract.

Identification and characterization of thermophilic bacteria isolated from hot springs in Turkey

The present study was conducted to identify and characterize the thermophilic bacteria isolated from various hot springs in Turkey by using phenotypic and genotypic methods including fatty acid methyl ester and rep-PCR profilings, and 16S rRNA sequencing. The data of fatty acid analysis showed the presence of 17 different fatty acids in 15 bacterial strains examined in this study. Six fatty acids, 15:0 iso, 15:0 anteiso, 16:0, 16:0 iso, 17:0 iso, and 17:0 anteiso, were present in all strains. The bacterial strains were classified into three phenotypic groups based on fatty acid profiles which were confirmed by genotypic methods such as 16S rRNA sequence analysis and rep-PCR genomic fingerprint profiles. After evaluating several primer sets targeting the repetitive DNA elements of REP, ERIC, BOX and (GTG)(5), the (GTG)(5) and BOXA1R primers were found to be the most reliable technique for identification and taxonomic characterization of thermophilic bacteria in the genera of Geobacillus, Anoxybacillus and Bacillus spp. Therefore, rep-PCR fingerprinting using the (GTG)(5) and BOXA1R primers can be considered as a promising genotypic tool for the identification and characterization of thermophilic bacteria from species to strain level.

Characterization of Thermophilic Bacteria Using Surface-Enhanced Raman Scattering

Surface-enhanced Raman scattering (SERS) can provide molecular-level information about the molecules and molecular structures in the vicinity of nanostructured noble metal surfaces such as gold and silver. The three thermophilic bacteria Bacillus licheniformis, Geobacillus stearothermophilus, and Geobacillus pallidus, a Gram-negative bacterium E. coli, and a Gram-positive bacterium B. megaterium are comparatively characterized using SERS. The SERS spectra of thermophilic bacteria are similar, while they show significant differences compared to E. coli and B. megaterium. The findings indicate that a higher number of thiol residues and possible S–S bridges are present in the cell wall structure of thermophilic bacteria, providing their stability at elevated temperatures. Incubating the thermophilic bacteria with colloidal silver suspension at longer times improved the bacteria–silver nanoparticle interaction kinetics, while increased temperature does not have a pronounced effect on spectral features. A tentative assignment of the SERS bands was attempted for thermophilic bacteria. The results indicate that SERS can be a useful tool to study bacterial cell wall molecular differences.

Purification and biochemical characterization of a novel thermostable serine alkaline protease from Aeribacillus pallidus C10: a potential additive for detergents

Abstract An extracellular thermostable alkaline serine protease enzyme from Aeribacillus pallidus C10 (GenBank No: KC333049), was purified 4.85 and 17. 32-fold with a yield of 26.9 and 19.56%, respectively, through DE52 anion exchange and Probond affinity chromatography. The molecular mass of the enzyme was determined through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), with approximately 38.35 kDa. The enzyme exhibited optimum activity at pH 9 and at temperature 60 °C. It was determined that the enzyme had remained stable at the range of pH 7.0–10.0, and that it had preserved more than 80% of its activity at a broad temperature range (20–80 °C). The enzyme activity was found to retain more than 70% and 55% in the presence of organic solvents and commercial detergents, respectively. In addition, it was observed that the enzyme activity had increased in the presence of 5% SDS. KM and Vmax values were calculated as 0.197 mg/mL and 7.29 μmol.mL−1.min−1, respectively. Graphical Abstract

Purification and characterization of β -mannanase from Bacillus pumilus (M27) and its applications in some fruit juices

Thermo alkaline mannanase was purified from the bacteria of Bacillus pumilus (M27) using the techniques of ammonium sulphate precipitation, DEAE-Sephadex ion exchange chromatography and Sephacryl S200 gel filtration chromatography with 111-fold and 36 % yield. It was determined that the enzyme had 2 sub-units including 35 kDa and 55 kDa in gel filtration chromatography and SDS-PAGE electrophoresis systems. The optimum pH and temperature was determined as 8 and 60 °C, respectively. It was also noticed that the enzyme did not lose its activity at a wide interval such as pH 3–11 and at high temperatures such as 90 °C. Additionally, the effects of some metal ions on the mannanase enzyme activity. Moreover, the clarifying efficiency of purified mannanase enzyme with some fruit juices such as orange, apricot, grape and apple was also investigated. Enzymatic treatment was carried out with 1 mL L−1 of purified mannanase for 1 h at 60 °C. It was determined that the highest pure enzyme was efficient upon clarifying the apple juice at 154 % rate.

Biochemical Evaluation and Green Synthesis of Nano Silver Using Peroxidase from Euphorbia (Euphorbia amygdaloides) and Its Antibacterial Activity

Silver nanoparticles are used an increased attention for various biomedical and medical applications. In this study, green synthesis of silver nanoparticles was made with simple method by using peroxidase enzyme partially purified from Euphorbia (Euphorbia amygdaloides) plant. Optimum pH, temperature and time period were determined to obtain silver nanoparticles using the peroxidase enzyme. The result shows that higher silver nanoparticle was synthesized for 4 hours and at 20°C and pH 8. Also, optimal concentration of metal ions was found as 0.5 mM. The synthesized silver nanoparticles were characterized by UV spectrum, scanning electron microscope (SEM) and X-ray diffraction. Antibacterial activity of silver nanoparticles was measured against some microorganisms such as Serratia marcescens, Yersinia pseudotuberculosis, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Listeria monocytogenes, and Escherichia coli. Synthesized silver nanoparticles have wide spectrum antibacterial activity in low concentration and may be a good alternative therapeutic approach in medicine and pharmaceutical fields in future.

Conventional and Molecular Identification of Bacteria with Magnesite Enrichment Potential from Local Quarries in Erzurum

In this study, the bacteria having ore enrichment potential were isolated from three different magnesite quarries located in Erzurum-Askale borderlines. The obtained isolates were identified and characterized according to the conventional (morphological, physiological and biochemical tests) and molecular techniques (fatty acid methyl ester profiles (FAME), BOX PCR and 16S rDNA). According to sequence analysis, they were determined as Exiguobacterium aurantiacum (4), Exiguobacterium sibiricum (2), Bacillus sp. (2), Staphylococcus epidermidis (2), Staphylococcus haemolyticus (1), Shewanella baltica (1) and Klebsiella oxytoca (1), respectively.

Isolation and Characterization of Thermophilic Bacteria from Geothermal Areas in Turkey and Preliminary Research on Biotechnologically Important Enzyme Production

ABSTRACT In this study, the isolation, identification and characterization of the thermophilic bacteria from different hot springs in Turkey were carried out by conventional (morphological, physiological and biochemical tests) and molecular methods (fatty acid methyl esters, GTG5-PCR and 16S rRNA sequencing). These thermophilic bacteria were then tested for their capability to produce enzymes such as lipase, protease, amylase and cellulase. O20 strain is a novel species according to identification studies. All of its isolates were capable of producing industrially valuable enzymes based on screening. In fact, most of them could produce at least two of these enzymes.

Determination of antimutagenic properties of apigenin-7-O-rutinoside, a flavonoid isolated from Mentha longifolia (L.) Huds. ssp. longifolia with yeast DEL assay

Lamiaceae is an important plant family that has been investigated for its medicinal properties due to its large amounts of phenolic acids and flavonoids. Flavonoids have been shown to have antioxidant and antimutagenic activities in different test systems, but their certain mechanisms are still unclear. This study was designed to evaluate the mutagenic and antimutagenic activities of apigenin 7-O-rutinoside, a flavonoid isolated from Mentha longifolia (L.) Huds. ssp. longifolia. The possible antimutagenic potential of apigenin 7-O-rutinoside (A7R) was examined against mutagens ethyl methanesulfonate (EMS) and acridine (AC) in a eukaryotic cell system Saccharomyces cerevisiae RS112. The results showed that A7R has different inhibition rates against EMS and AC-induced mutagenicity. Thus, the properties of A7R are of great pharmacological importance and might be beneficial for reducing the risk of reactive oxygen species–related diseases.