Sahlan Ozturk

Antimicrobial and antioxidant activities of Russula delica Fr.

Russula delica Fr. is a well known macrofungi which is used as a food in Turkey. The ethanolic extract of R. delica exhibited antimicrobial activity against some of the tested foodborne and spoilage bacteria. The phenolic composition of R. delica ethanolic extract was analyzed by high performance liquid chromatography (HPLC). The major component in R. delica ethanolic extract was catechin (5.33 mg/L). Antioxidant activities of the ethanolic extract of R. delica was evaluated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging and chelating ability on ferrous ions assays. Scavenging effect on DPPH radicals was 26% at 10mg/ml and chelating effects on ferrous ions was 58% at 5mg/ml. In addition, the amounts of total phenol content (6.23 mg/g), ascorbic acid (2.93 mg/g), beta-carotene (0.11 mg/g) and lycopene (0.03 mg/g) in the macrofungi ethanolic extract were determined.

Evaluation of chromium(VI) removal behaviour by two isolates of Synechocystis sp. in terms of exopolysaccharide (EPS) production and monomer composition

Chromium(VI) removal and its association with exopolysaccharide (EPS) production in cyanobacteria were investigated. Synechocystis sp. BASO670 produced higher EPS (548 mg L(-1)) than Synechocystis sp. BASO672 (356 mg L(-1)). While the EC(50) of the Cr(VI) for Synechocystis sp. BASO670 and Synechocystis sp. BASO672 were determined as 11.5 mg L(-1), and 2.0 mg L(-1), respectively, there was no relation between Cr(VI) removal and EPS production. Synechocystis sp. BASO672, which has higher EPS value, removed (33%) more Cr(VI) than Synechocystis sp. BASO670. Monomer compositions of EPS of each of the isolates were determined differently. Synechocystis sp. BASO672 which removed higher Cr(VI), had higher values of uronic acid and glucuronic acid (192 microg/mg and 89%, respectively). Our results showed that EPS might play a role in Cr(VI) tolerance. Monomer composition, especially uronic acid and glucuronic acid content of EPS may have enhanced Cr(VI) removal.

Cadmium(II) sequestration characteristics by two isolates of Synechocystis sp. in terms of exopolysaccharide (EPS) production and monomer composition

We investigated cadmium(II) resistance and its association with exopolysaccharide (EPS) production in cyanobacteria. Increased EPS production was associated with Cd(II) resistance. The most resistant isolate, Synechocystis sp. BASO670, secreted the greatest amount of EPS (548 mg/L). EPS production by Synechocystis sp. BASO670 and Synechocystis sp. BASO672 was increased following exposure to 15 and 35 ppm Cd(II). Monomer composition of EPS belonging to each isolate was changed after Cd(II) treatment. Uronic acid contents of Cd(II) treated cells were higher than control cells of each isolate. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis confirmed that a considerable amount of metals had precipitated on the cell surface. Fourier transform infrared (FT-IR) spectrum analysis of EPSs belonging to both isolates indicated the presence of C-H and C-O group, which may serve as binding sites for divalent cations.

Removal and reduction of chromium by Pseudomonas spp. and their correlation to rhamnolipid production

Chromium removal and its association with rhamnolipid production in Pseudomonas spp. were investigated. Three Pseudomonas spp. isolates (P. aeruginosa 78, P. aeruginosa 99, and P. stutzeri T3) were investigated with regard to their exposure to 10mg/L for chromium removal. P. aeruginosa 99 removed 16% and 20% more chromium than P. stutzeri T3 and P. aeruginosa 78 respectively. The reduction of Cr(VI) to Cr(III) by all the three isolates is more or less similar. P. aeruginosa 99, which removed higher chromium, also produced higher rhamnolipid (165±5 mg/mL). P. aeruginosa 78, which removed lower chromium, also produced lower rhamnolipid (126±3 mg/mL). Rhamnolipid production by P. aeruginosa 78 and P. aeruginosa 99 was increased in its exposure to 10mg/L chromium. In the present study, results showed that rhamnolipid might play a role in chromium removal by three Pseudomonas spp. isolates.

Metal removal of cyanobacterial exopolysaccharides by uronic acid content and monosaccharide composition

In the present study, chromium, cadmium and metal mixed (chromium+cadmium) removal and its association with exopolysaccharides and uronic acids production in Synechocystis sp. BASO671 were investigated. It was investigated that BASO671 showed different removal ability when exposed to each metal solely and mixed metal. EPS production by BASO671 was increased following exposure to 15 and 35 ppm Cr(VI), Cd(II) and Cr(VI)+Cd(II). Monomer composition of EPS was changed after metal treatment. Uronic acid contents of metal treated cells were higher than control cells of each isolate. Also, glucuronic acid content and galactronic acid content of EPS correlated with uronic acid contents of cells. Scanning electron microscopy and energy dispersive X-ray spectroscopy analysis confirmed that a considerable amount of metals had precipitated on the cell surface. Fourier transform infrared spectrum analysis of EPSs indicated the presence of CH and CO group, which may serve as binding sites for divalent cations.

Characterization of vaginal lactobacilli coaggregation ability with Escherichia coli

The coaggregation abilities of probiotic strains might enable it to form a barrier that prevents colonization by pathogenic bacteria. In the present study, the characterization of the coaggregation ability of 19 vaginal lactobacilli was studied. Coaggregation ability of all lactobacilli with Escherichia coli ATCC 11229 was positive. Only the highest coaggregation percentage of Lactobacillus acidophilus S1 was obtained with E. coli ATCC 11229 under both aerobic (71%) and anaerobic conditions (62%). The coaggregation abilities of strains occurred higher at acidic pH than at basic pH values. Moreover, the coaggregation abilities of tested strains against E. coli decreased after heat treatment (70 or 85 °C). Also, the relationship between hydrophobicity and coaggregation of strains was found to be significant. The effect of sonication, some enzymes (lipase and pepsin) and sodium periodate on coaggregation ability of L. acidophilus S1, which is one of the highest potentials on coaggregation ability, was investigated. Sodium periodate did not have a significant effect on coaggregation ability of L. acidophilus S1. The sonicated cell showed lower coaggregation than the control, the supernatant fluid of this sonicated cells showed similar coaggregation ability to the control. Coaggregation abilities of bacteriotherapeutic lactobacilli with pathogenic bacteria can be used for preliminary screening in order to identify potentially probiotic bacteria suitable for human use against urogenital tract infections.

Phenylalanine ammonia lyase (PAL) enzyme activity and antioxidant properties of some cyanobacteria isolates

In the present study, six cyanobacteria isolates were evaluated for the PAL enzyme activity, and their methanol extracts were assessed for the total phenolic amount and other antioxidant parameters. Synechocystis sp. BASO444 and Synechocystis sp. BASO673 isolates with high levels of total phenols (66.0±1.2μg/mg, 78.1±1.8μg/mg, respectively) also showed high levels of PAL activities (20.5±3.1U/mg protein, 17.2±2.3U/mg protein, respectively) and strong antioxidant activities. To understand the effect of l-phenylalanine (l-phe) on the PAL activity, total phenolic amount, and phenolic constituents, isolates were evaluated with 100mg/l l-phe. While PAL activities exhibited no significant change with l-phe addition, total phenolic amount of the isolates significantly increased. HPLC analysis revealed gallic acid, trans-cinnamic acid, p-coumaric acid, and ferulic acid as the main compounds. Results suggested that the two isolate mights be an important source for the l-phe inducible phenolic compounds.

The synthesis and investigation of the antimicrobial activity of some new phenylselanyl-1-(toluene-4-sulfonyl)-1H-tetrazole derivatives

The sulfonamide functional group has aroused interest in both medicinal and bioorganic chemistry. In this study, some new phenylselanyl–1–(toluene-4-sulfonyl)-1H-tetrazole derivatives (2a–f) have been synthesized using dicyclohexylcarbodiimide/dimethylaminopyridine (DCC/DMAP). The structures of the presently synthesized compounds were elucidated by spectroscopic methods [Fourier-transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (NMR), 13C nuclear magnetic resonance-attached proton test (13C NMR-APT), and mass spectrometry (MS)]. In addition, the antimicrobial activity of the synthesized compounds and two antibiotics [sulfamethoxazole (SMX) and sulfamerazine (SRZ)] were investigated against some microorganisms.Graphical AbstractThe synthesis and investigation of the antimicrobial activity of some new phenylselanyl-1-(toluene-4-sulfonyl)-1H-tetrazole derivativesYılmaz Yıldırır, M. Faruk Us, Naki Çolak, Hamdi Özkan, Serkan Yavuz, Ali Disli, Sahlan Ozturk, Lemi TurkerIn this study, some new phenylselanyl–1–(toluene-4-sulfonyl)-1H- tetrazole derivatives, 2a–f, have been synthesized using DCC/DMAP. In addition to, antimicrobial activity of synthesized compounds and two antibiotics (SMX, SRZ) were investigated against some microorganisms. Reagents and conditions: (i) HCI, (ii) EtONO, -5 – 0°C; (iii) KSeCN, (iv) NaN3, Et3NH+ CI−, Toluene. 2a. R1:H, R2:Cl 2b. 2a. R1:H, R2:CH32c. R1:Cl, R2:H 2d. R1:Br, R2:H 2e. R1:I, R2:H 2f. R1:CH3, R2:H

Phenolic composition and antimicrobial and antioxidant activities of Leucoagaricus leucothites (Vittad.) Wasser.

Leucoagaricus leucothites (Vittad.) Wasser is an edible macrofungus found limitedly in Turkey. The ethanolic extract of L. leucothites has shown strong antimicrobial activity against some foodborne and spoilage bacteria. Therefore, the phenolic composition of L. leucothites ethanolic extract was analyzed by using high-performance liquid chromatography. Catechin (288 mg/L) was found to be the major component in the extract. Antioxidant activity of the extract was evaluated by studying the scavenging ability of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, and chelating ability of the extract was assessed in a ferrous ion assay. The scavenging effect on DPPH radicals was 71% at 10 mg/mL, whereas the chelating effect on ferrous ions was 82% at 15 mg/mL. The total contents of phenol (3.40 ± 0.5 mg/g), ascorbic acid (2.10 ± 0.3 mg/g), β-carotene (0.02 ± 0.0 mg/g), and lycopene (0.01 ± 0.0 mg/g) in the macrofungi ethanolic extract were also determined.