Biofilm Formation by Salmonella enterica Strains.

Biofilm formation by five different Salmonella enterica strains was assessed qualitatively and quantitatively under different incubation conditions. The strains exhibited different adherence abilities to test tubes. The isolates revealed Red Dry and Rough (RDAR) and Brown Dry and Rough (BDAR) morphotypes when cultured on Congo Red Agar (CRA). The pellicles formed by the tested strains ranged from strong to fragile when incubated in LB without NaCl at 27 °C. Smooth and White (SAW) morphotype on CRA and very weak pellicles were observed when the bacterial strains were incubated at 37 °C. The effect of temperature and media on biofilm formation by the tested strains was significant. Among the five Salmonella isolates, S. enteritidis TM 6 and S. enteritidis TM 68 formed strong biofilms when incubated in LB without NaCl at 27 °C for 24 h and consequently selected to be analysed under scanning electron microscope (SEM). Scanning electron micrographs revealed that S. enteritidis TM 6 formed more complex colonies when compared to those formed by S. enteritidis TM 68. As far as we know, this is the first study that provides quantitative and qualitative data for 5 Salmonella enterica isolates in different media mimicking four different nutritional conditions at two different temperatures after 24 and 48 h. The strains included two serovars S. bredeney and S. anatum, which are rarely accounted for. Additionally, the studies that described S. enteritidis biofilms under SEM are extremely limited, which makes it among the first comprehensive studies that screened for S. enteritidis biofilms.

Cytotoxic, antimicrobial and nitric oxide inhibitory activities of supercritical carbon dioxide extracted Prunus persica leaves.

Different parts of Prunus persica as fruits, flowers, leaves and kernels have been consumed with dietary and therapeutic purposes traditionally. During fruit production, remarkable amount of leaves which can hold important bioactive groups as phenolics, have been left unutilized. The aim of this study was to investigate cytotoxic, antimicrobial and nitric oxide inhibitory activities of supercritical carbondioxide extracts of Prunus persica leaves. Among studied cell lines, supercritical carbon dioxide extract which was processed at 150 bar, 60 °C, and 6% co-solvent ethanol, exhibited remarkable cytotoxic activity against HeLa, MPanc-96 and MCF-7 cell lines with IC50 values of 12.22 µg/ml, 28.17 µg/ml and 35.51 µg/ml respectively, whereas IC50 value of conventional solvent extract was above 50 µg/ml. Minimum inhibitory concentration values determined for antibacterial and antifungal activities against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium and Candida albicans were found as 62.50 µg/ml. Strong nitric oxide inhibition was achieved with IC50 of 9.30 µg/ml. The promising results revealed that Prunus persica leaves may have remarkable potential as supplement both for drug and food industries. This study is the first report revealing cytotoxic, antimicrobial and nitric oxide inhibitory activity of supercritical carbon dioxide extract of Prunus persica leaves.

Biological activities of skin and parotoid gland secretions of bufonid toads (Bufo bufo, Bufo verrucosissimus and Bufotes variabilis) from Turkey.

Toad glandular secretions and skin extractions contain numerous natural agents which may provide unique resources for novel drug development. Especially the skin-parotoid gland secretions of toads from genus Bufo contain as many as 86 different types of active compounds, each with the potential of becoming a potent drug. In the present study, crude skin-parotoid gland secretions from Bufo bufo, Bufo verrucosissimus and Bufotes variabilis from Turkey were screened against various cancer cells together with normal cells using MTT assay. Furthermore, the antimicrobial properties of skin secretions were tested on selected bacterial and fungal species for assessing the possible medical applications. Antimicrobial activity of skin secretions was studied by determining minimal inhibitory concentration (MIC) in broth dilution method. Hemolytic activity of each skin-secretion was also estimated for evaluating pharmaceutical potential. Both skin-parotoid gland secretions showed high cytotoxic effect on all cancerous and non-cancerous cell lines with IC50 values varying between <0.1µg/ml and 6.02µg/ml. MIC results of antimicrobial activity tests were found to be between 3.9µg/ml and 250µg/ml. No hemolytic activities on rabbit red blood cells at concentrations between 0.5µg/ml and 50µg/ml were observed. In conclusion, skin-parotoid secretions of bufonid toads might be remarkable candidates for anti-cancer and antimicrobial agents without hemolytic activities.

Essential Oil Composition of Pimpinella cypria and its Insecticidal, Cytotoxic, and Antimicrobial Activity.

A water-distilled essential oil (E) from the aerial parts of Pimpinella cypria Boiss. (Apiaceae), an endemic species in northern Cyprus, was analyzed by GC- FID and GC-MS. Forty-five compounds were identified in the oil, which comprised 81.7% of the total composition. The compound classes in the oil were oxygenated sesquiterpenes (33.9%), sesquiterpenes (22.0%), monoterpenes (11.4%), oxygenated monoterpenes (2.6%), and phenylpropanoids (7.5%). The main components of the oil were (Z)-ß-farnesene (6.0%), spathulenol (5.9%), ar-curcumene (4.3%), and 1,5-epoxy-salvial(4)14-ene (3.8%). The P. cypria EO deterred yellow fever mosquitoes (Aedes aegypti) from biting at a concentration of 10 µg/cm2 in in vitro bioassays. The oil was tested for repellency in assays using human volunteers. The oil had a minimum effective dosage (MED) for repellency of 47 ± 41 µg/cm² against Ae. aegypti, which was less efficacious than the positive control NN-diethyl-3-methylbenzamide (DEET). In larval bioassays, P. cypria EO showed an LC50 value of 28.3 ppm against 1st instar Ae. aegypti larvae. P. cypria EO demonstrated dose dependent repellency against nymphs of the lone star tick, Amblyomma americanum. Between 45.0% and 85.0% repellency was observed at concentrations ranging from 26 to 208 µg/cm². However, P. cypria EO was less effective compared with DEET in the tick bioassays. Cytotoxicity assays showed that the P. cypria EO did not exhibit significant effects up to the maximum treatment concentration of 50 µg/mL on HEK293, PC3, U87MG, and MCF cells. P. cypria EO also demonstrated moderate antimicrobial activity against Gram-negative and -positive bacteria with MICs ranging from 15.6 to 62.5 µg/mL, except for Candida albicans, which showed the same MIC value of 7.8 µg/mL as the positive control, flucytosine. This is the first report on the chemical composition of P. cypria EO and its insecticidal, toxicant, cytotoxic, and antimicrobial activity.

Effect of Ottoman Viper (Montivipera xanthina (Gray, 1849)) Venom on Various Cancer Cells and on Microorganisms.

Cytotoxic and antimicrobial effects of Montivipera xanthina venom against LNCaP, MCF-7, HT-29, Saos-2, Hep3B, Vero cells and antimicrobial activity against selected bacterial and fungal species: Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, E. coli O157H7, Enterococcus faecalis 29212, Enterococcus faecium DSM 13590, Staphylococcus epidermidis ATCC 12228, S. typhimirium CCM 5445, Proteus vulgaris ATCC 6957 and Candida albicans ATCC 10239 were studied for evaluating the potential medical benefit of this snake venom. Cytotoxicity of venom was determined using MTT assay. Snake venom cytotoxicity was expressed as the venom dose that killed 50 % of the cells (IC50). The antimicrobial activity of venom was studied by minimal inhibitory concentration (MIC) and disc diffusion assay. MIC was determined using broth dilution method. The estimated IC50 values of venom varied from 3.8 to 12.7 or from 1.9 to 7.2 µg/ml after treatment with crude venom for 24 or 48 h for LNCaP, MCF-7, HT-29 and Saos-2 cells. There was no observable cytotoxic effect on Hep3B and Vero cells. Venom exhibited the most potent activity against C. albicans (MIC, 7.8 µg/ml and minimal fungicidal concentration, 62.5 µg/ml) and S. aureus (MIC, 31.25 µg/ml). This study is the first report showing the potential of M. xanthina venom as an alternative therapeutic approach due to its cytotoxic and antimicrobial effects.