Hüsniye Tansel Yalçın

Screening of cytotoxic and antimicrobial activity potential of Anatolian Macrovipera lebetina obtusa (Ophidia: Viperidae) crude venom

The effects of snake venoms have been well known since ancient times. They contain a variety of biologically active proteins which have therapeutic potential. This study investigated the cytotoxic and antimicrobial activities of Anatolian Macrovipera lebetina obtusa venom against various cancer cells, Gram-negative and Gram-positive bacteria, and a fungal species. A549, HeLa, CaCo-2, U-87 MG and MCF-7 cancer cell lines and a normal cell line (Vero) were screened by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The antimicrobial activity was evaluated by determining the minimum inhibitory concentration (MIC) using the broth dilution method. The species included were Escherichia coli ATCC 25922, E. coli 0157:H7, Enterococcus faecalis, Enterococcus faecium DSM 13590, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Salmonella typhimurium CCM 5445, Proteus vulgaris ATCC 6957, Bacillus cereus ATCC 7064 and Candida albicans ATCC 10239. Half-maximal inhibitory concentration (IC50) values of M. l. obtusa venom on cultured cells varied from 1.18 ± 0.11 to 12.80 ± 0.22 µg/ml, with the most potent activities against Vero, U-87 MG, MCF-7 and CaCo-2 cells. Venom showed moderate antifungal activity against C. albicans, with an MIC of 62.50 µg/ml. In short, the venom of Anatolian M. l. obtusa showed promising results as a potential source of alternative therapeutics, cytotoxic and antifungal agent prototypes.

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.

Screening of cytotoxic, anti-angiogenic, anti-tumorogenic and antimicrobial activities of Anatolian Vipera ammodytes (Nose-horned viper) venom

Abstract Objective: In the present study, we aimed to screen the cytotoxic, antimicrobial, anti-angiogenic and anti-tumorogenic activities of Anatolian Vipera ammodytes (Nose-horned Viper) crude venom. Material and methods: The cytotoxicity was screened against PC3, HeLa, CaCo-2, U-87MG, MCF-7 and Vero cells by using MTT assay. The antimicrobial activity on Escherichia coli ATCC 25922, E. coli 0157:H7, Enterococcus faecalis 29212, Enterococcus faecium DSM 13590, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Salmonella typhimirium CCM 5445, Proteus vulgaris ATCC 6957, Bacillus cereus ATCC 7064 and Candida albicans ATCC 10239 was assayed by determining the minimum inhibitory concentration using the broth dilution method. Anti-angiogenic and anti-tumorogenic activity was assessed by using chick chorioallantoic membrane (CAM) assay. Results: The IC50 value of V. ammodytes venom on cultured cells varied from 1.8 to 7.0 μg/mL after 48 h treatment. Venom showed antimicrobial activity on P. vulgaris, S. aureus, S. epidermidis, E. faecium and C. albicans (the highest activity). The venom exhibited dose-dependent anti-angiogenic activity on CAM model at 2 and 10 μg/mL doses with scores of 1.1 and 2.0, respectively. Conclusion: The results of the present study contributed to the knowledge of the biological activities of Anatolian V. ammodytes venom and showed its potential for further bioactivity guided characterization studies.

Major biological activities and protein profiles of skin secretions of Lissotriton vulgaris and Triturus ivanbureschi

Abstract Objective The aim of this study was to determine the total protein amounts, protein profiles, in vitro cytotoxicities, antimicrobial activities and hemolytic effects of skin secretions of the Lissotriton vulgaris and Triturus ivanbureschi. Methods Skin secretions were obtained, clarified, supernatants snap-frozen then lyophilized. Total protein amounts were determined by BCA assay kit. Protein profiles were revealed by the SDS-PAGE. The cytotoxicity and antimicrobial activity were determined by using MTT assay and minimum inhibitory concentration (MIC) method. Hemolytic effects were measured on rabbit red blood cells. Results Lissotriton vulgaris and T. ivanbureschi skin secretions have totally 18 and 20 protein fractions. IC50 values were detected between 1.40 and 40.28 μg/mL. The MIC results were found between 7.8 and 250 μg/mL. Lissotriton vulgaris skin secretion showed low hemolytic effect while T. ivanbureschi skin secretion showed high hemolytic effect. Conclusion This study is the first report showing the potential of L. vulgaris and T. ivanbureschi skin secretions for cytotoxicity, antimicrobial and hemolytic activity as an alternative therapeutic approach for traditional uses. Further studies need to focus on purification of the active components from these skin secretions and mode of action on cancer cell lines and microorganisms as anti-agents.

Isolation and molecular characterization of biosurfactant producing yeasts from the soil samples contaminated with petroleum derivatives

In this study, 65 yeast strains were isolated from different environmental samples contaminated with various petroleum hydrocarbons such as activated sludges and soil samples from automobile workshops. The yeast isolates were tested for biosurfactant production using various screening methods such as parafilm M test, oil displacement assay, drop collapse assay, determination of surface tension reduction, and emulsification index. Nineteen of the isolates were found positive for biosurfactant production and their molecular characterizations were carried out by sequencing analysis of the ITS1‐5.8S‐ITS2 region and D1/D2 domain of 26S rDNA. The results indicated that these strains were from a wide range of yeast genera including Rhodotorula, Candida, Yarrowia, Geotrichum, Galactomyces, and Cystobasidium. The studies to determine the emulsification index revealed that the biosurfactants produced by Yarrowia lipolytica strains (TEMGS33, TEMOS12, and TEMOS14) and Apiotrichum loubieri strain (TEMOS16) were the most potent and capable of forming stable emulsions with emulsion index (E24) up to 68%. In addition, quantitative measurements of the surface tension reduction of the biosurfactants produced by these strains were carried out by Du Noüy ring method. Biosurfactants produced from Yarrowia lipolytica strain TEMGS33 and Apiotrichum loubieri strain TEMOS16 gave the best results reducing the surface tension to 34.7 ± 1.15 and 35.3 ± 0.55 mN m−1, respectively. Based on these data, biosurfactants from Yarrawia lipolytica strains (TEMGS33, TEMOS12, and TEMOS14) and Apiotrichum loubieri strain (TEMOS16) showed promising results and might be implemented in numerous industrial fields such as bioremediation and food industry.